Your guide to age fifteen

This guide is intended to provide some context into what you might expect for neuro-typical fifteen-year-old development. Milestones and development are different for everyone.

Technically still an “early-adolescent,” your teen’s more mature adult physical appearance may mask their still-developing brain. Their ability to cope and process the rapid changes happening around them may depend on how they feel at that moment. Fifteen-year-olds can seem moody, unpredictable, confusing, and even challenging for adults, parents, and caregivers. You’ll notice your teen testing limits, spending less time with you and more with friends, and wanting more privacy.

Your job as a parent or trusted adult is to stick by them, even through ups and downs. Establishing connection and clear expectations for your teen can help keep them safe, healthy and limit risk-taking behaviors. In addition, learning more about some of the normal developmental milestones you may see your 15-year-old reach during this year will help you stay the course on their journey from adolescence to adulthood. 

The major developmental milestones for 15-year-olds

Age 15 language and cognitive skills development

Cognitive development is the changes that happen in the brain to allow your teen to think and learn. You can think of developmental milestones as checkpoints along their path to developing an adult-thinking brain. 

By Age 15, your child may:

  • Use abstract thinking to form new ideas and questions.
  • Solve complex, higher-order math problems.
  • Have improved memory (both long-term and working memory).
  • Exhibit selective attention (i.e., the ability to answer your questions while scrolling through social media).
  • Formulate goals for the future.
  • May still act impulsively and not think about the consequences of their actions “in the moment.”
  • Earn and spend money wisely.
  • Able to think more quickly (called processing speed).
  • Know the meaning of more than 30,000 words.

Age 15 social and emotional learning milestones

You may notice your 15-year-old starting to:

  • Explore different identities to help them find where they fit in. This can include gender questioning and gender fluidity
  • Have sexual feelings. This may lead to dating, relationships, and exploring their sexuality through masturbation.
  • Want to explore boundaries and engage in risky behaviors. But, developmentally, they still have the invincible “it will never happen to me” mind-set.
  • Argue more as they attempt to assert their independence and growing need for control.
  • Pull away from you and other caregivers more and more.
  • Turn to friends as their primary social support.
  • Seek out and value their privacy.

Age 15 physical development and motor skills

The physical changes of adolescence can make teens increasingly self-conscious. Your child may go through an awkward stage in their physical appearance, muscular coordination, and social interactions at this age. 

By age 15:

  • Breast development,pubic hair growth, full adult height, and first menstrual periods are all likely in the rear view mirror. Talk with a healthcare provider if your teen has not started menstruating or is experiencing heavy, irregular, or painful periods.
  • Puberty will have caused penises to grow longer, the testicles to get bigger, and the growth of facial, armpit, and pubic hair.
  • Your teen may have started having wet dreams (nocturnal emissions). 
  • They may seem clumsy or uncoordinated as their brain struggles to catch up with rapid height and muscle mass changes.
  • Increases in body size, hormones, and muscle strength can improve athletic performance.

Vaccines for 15-year-olds

Keeping your 15-year-old up-to-date with their recommended vaccines will protect them from serious illnesses. They should receive catch-up vaccines if they are off schedule. Ask about getting catch-up vaccines at your teen’s camp and sports physical appointments. The vaccines your 15-year-old might receive this year include the following:

  • Influenza (Flu) (one dose of vaccine every year)
  • COVID-19 (per current CDC recommendations)

Healthy eating and activity for 15-year-olds

Healthy eating can be more challenging as adolescents become more independent and make more food decisions without your involvement. It’s not just about providing meals anymore! Many adolescents experience a growth spurt and an increased appetite and need more food to fuel their growth. Talk with your healthcare provider if it is hard for you to provide enough for your growing teen to eat.

  • Encourage your teen to help you meal plan and make grocery lists. Throw in some ideas about budget for bonus points!
  • Some adolescents can have low calcium, iron, zinc, or vitamin D. Talk with your child’s healthcare provider if you have concerns or questions about dietary supplements.
  • Limit 100% juice, sports drinks, and other sugary beverages to no more than 4–6 ounces (120–180 ml) daily. Teach them about the health risks of energy drinks and drinking too much caffeine.
  • Stock up on their favorite  fruits and vegetables for snacks (5 servings per day are recommended).
  • Your teen should brush their teeth twice daily, floss once daily, and see a dentist every 6 months.
  • Your teen should be getting physical activity each day for about 60 minutes.
  • If your teen is overweight or inactive, they might need to start physical activity slowly. If your teen has a chronic health condition or disability, there are likely ways to introduce enjoyable movement.Talk with their healthcare provider about safe physical activity and which activities can be adapted or changed.
  • If your teen is an athlete, avoid specializing in one sport before late adolescence to prevent overuse injuries.
  • Watch for the signs of disordered eating that can emerge during the teenage years in all genders.
  • Your 15-year-old should get between 8-10 hours of sleep every night. Chronic sleep deprivation can lead to serious problems for your teen’s health and well-being.

Keeping your 15-year-old safe

  • Ensure your 15-year-old always wears a helmet for activities with a risk of hitting their head. Repeat concussions during adolescence with or without helmet use can have severe and lifelong health consequences.
  • Don’t even try it. Adolescence is the time when most people start smoking.
  • Discourage vaping. Using E-cigarettes or vaping in adolescence can cause lifelong problems for your teen’s mental health by harming the parts of their brain controlling attention, learning, mood, and impulse regulation.
  • Continue talking with your teens about drugs and alcohol. Nearly 30 percent of high schoolers say they’ve tried alcohol, and 14 percent admit to binge drinking. It’s never too late to start having these conversations if you haven’t already. These talks will open the door for support, and they will not encourage drug and alcohol use.
  • Reinforce the importance of always wearing seatbelts with your teen, and model their use every single drive.
  • Impaired drivers are a threat to your teen’s safety. Give your teen tips for getting out of riding with a driver impaired by alcohol or drugs. Give them a free pass to text you for a safe ride at any time.
  • Talk with your teen about gun safety and school violence. If you own a gun, re-evaluate safety measures to make sure it will stay out of your teen’s hands.
  • A child who expresses suicidal thoughts or is engaging in self-harm needs your help. Talk with your healthcare provider or a mental health professional about how to support your teen.
  • Your 15-year-old should continue to have annual check-up appointments with their pediatrician or healthcare provider. Respect their need for medical privacy if desired. Encourage your teen to ask questions about mental health, birth control or other sensitive topics if they are struggling to talk about it with you.
  • Gender-diverse teens are more likely to experience bullying, depression, and suicide. Make your home a safe space for your gender-diverse or gender-questioning teen with these resources for parents.
  • Are you worried about your 15-year-old’s eating habits, body image, or mental health? Contact your healthcare provider or a mental health professional specializing in eating disorders or adolescent obesity for additional support.

Safe and healthy screentime

Sleep disorders, behavior problems, loss of social skills, violence, and trouble with work and school can all result in teens spending too much time on screens. Talk with your 15-year-old about these health hazards and encourage healthy media behaviors such as:

  • Limiting the use of phones, devices, and social media to less than 2 hours of screen time daily. Talk about what happens if they break the rules ahead of time,  when you draft (or update) your family media agreement, like this one from Common Sense Media.
  • Set family ground rules for privacy. This will vary depending on your values and any history of misuse of social media. It is possible to respect your teen’s privacy while making them aware you will do some checking in. Safety check-ins and occasional monitoring will feel less like a violation if the ground rules are set as a team.
  • Most experts agree that passwords should be shared with parents so that in the event of an emergency or tech failure, someone else can help.
  • Monitor which games and apps your teen downloads and plays.
  • Talk about the mental and sexual health risk factors of sexting before you think you need to. Sexting is the sending or receiving of sexually explicit images, videos, or text messages using a smartphone, computer, tablet, video game, or digital camera. 
  • Ask your teen how their online activities make them feel. What teens think about their bodies affects their feelings of self-worth. Help your teen recognize that the media’s unrealistic images and use of filters distort our ideas about real beauty.
  • Encourage your teen’s healthy sexuality – teens who have discussed pornography with a trusted adult say that “the porn talk” made them feel better about sex and themselves.
  • Set a good example by being mindful of your own tech use. Why not try inviting your teen to do something together that doesn’t involve screens? Why not make some family rules about screens in the car or during meals?
  • Review the principles of digital citizenship and using the THINK model (asking if each message is True, Helpful, Inspiring, Necessary, and Kind before sending).  

Conversation starters and parenting hacks for your 15-year-old

Taking an interest in your teen’s life shows you care and builds trust. If they trust you (and your judgment), your teen will feel safe talking with you about sensitive subjects. 

Questions to ask your 15-year-old:

  • How have you experienced racism towards yourself or others? How did it make you feel?
  • What does stress feel like to you?
  • Have you ever tried to help someone who is being bullied? What happened? What would you do if it happened again?
  • Do all these school shootings in the news make you feel unsafe at school?
  • How male or female do you feel inside as you get older?
  • Are drug and alcohol use a big thing at your school?
  • What do you think your best quality is?
  • Do you think money can buy happiness?
  • How do you cheer yourself up?
  • What percentage of your classmates would you guess regularly watch pornography?
  • What do you think are some good reasons and bad reasons to become sexually active?

Not every talk with your teen needs to be about a serious subject, and you’d both be pretty exhausted if that were the case! You’ll also learn a lot about your teen from day to day “normal” conversations when you dig in and try to get a picture of their life. Ask about who they sat with at lunch. Ask about the clothes people were wearing. Help them paint a picture of a regular part of their day, so that you can “be there” for the memory. 

Ways to help them grow and develop:

  • Show your 15-year-old how to set goals. For example, talk about and write down a goal for the week, month, and year. Next, help your teen think about the steps needed to reach the goal. Work with them to make a schedule for each step. Talk about and praise their efforts, successes and even failures!
  • Help motivate your teenager to get off the couch and stay physically active by setting a good example.  Talk with your child about the physical benefits of exercise, such as improving mood or energy level. Many teens become less active in high school as organized sports activities become more competitive.
  • If someone tells a joke or you hear a song on the radio about something sexual, ask your 15-year-old if they know what it means. If they say yes, ask them to tell you “what kids think that means these days” – the meaning might differ from what you think. 
  • Talk about dating and sex earlier than you may think you need to. Focus on what makes a relationship healthy to help prevent teen dating violence. It is natural and normal for your adolescent to be interested in sexual topics – it does not mean your child is sexually active yet.
  • Involve your teen in setting household rules and schedules to encourage mature thinking.
  • Even if your teen doesn’t initiate conversations about issues of difference, ask them what they think about current topics from the news, such as the immigration debate or teaching about race in schools.
  • Notice changes in your teen’s sleeping and eating habits, any angry outbursts, mood swings, or a loss of interest in activities they used to love. These can all be subtle signs that your teen might be struggling. Check in with their teachers, coaches, health care providers, therapists, or counselors.
  • Encourage community service or volunteering to give them a chance to explore new skills, learn how to connect with others, and have the confidence to try new things.

Reviewed by the Ovia Health Clinical Team


Read more

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