18 Year-Old Child Development Milestones

Your child’s growth and development at age 18

Mother and daughter using laptop together at home.
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By age 18, many teens are feeling a combination of excitement and fear about the future. There are a lot of decisions about life after graduation and 18-year-olds invest a lot of time into thinking about what type of life they want once they're on their own.

Teens who have plenty of life skills often feel ready to move out of the home and begin the next chapter. But those who experience a lot of self-doubt may regress a bit as they think about entering the next phase of their lives.

Physical Development

By age 18, both boys and girls have physically matured. Puberty is over and they’ve usually reached their full height.

Boys may continue to grow a little more facial hair and their voices may still change a bit more, but otherwise, they’re living in adult bodies.

Many teens grow more comfortable with their bodies as they’ve had some time to adjust to the rapid changes they experienced during the earlier teen years.

Key Milestones

  • Growth has tapered or ended completely
  • Less preoccupation with body changes
  • Have reached sexual maturity

Parenting Tip

Remind your teen that his brain isn’t yet fully developed. Drinking alcohol at this age could affect his brain development.

Emotional Development

Eighteen-year-olds are beginning to figure out where they will fit into the adult world. It is a time for big changes that comes with a lot of freedom and happiness, along with feelings of nostalgia and apprehension.

Most 18-year-olds are more comfortable seeking advice from older people and their parents again. They realize that they need some guidance and help to navigate the adult world and they’re more open to feedback than they were during their younger teen years.

They have much better control over their emotions by this age. And most 18-year-olds are equipped to deal with a wide variety of emotions.

The fear of the future—as well as the fear of failure—can still be problems, however. Some 18-year-olds will begin to resolve these issues successfully, while others will continue to struggle well into their adult lives.

Key Milestones

  • More comfortable seeking adult advice
  • Accepts adult responsibilities
  • Able to manage emotions in a socially acceptable manner

Parenting Tip

Normalize your teen’s emotions. Many 18-year-olds think they’re alone in their fears or they think they’re the only one without a solid plan for the future. Remind your teen she doesn’t have to have every aspect of her future career planned out.   

Social Development

Most 18-year-olds have had intimate relationships. They have a better understanding and awareness of their sexuality at this age.

Peer groups have less of a pull on 18-year-olds. They’re better able to evaluate their opinions without adopting the same ideas as everyone around them. Many of them take strong stances on social issues.

They have an emerging ability to make independent ​decisions and to compromise. This serves them well as they are forming new friendships and intimate relationships.

While most of them aren’t ready to settle with a partner, many of them are beginning to think about what they want in a future mate.

Key Milestones

  • Able to evaluate their own opinions instead of going along with the crowd
  • Intimate relationships are important
  • Accepts adult responsibilities

Parenting Tip

Talk to your teen about friendships beyond high school. Discuss whether your teen thinks he’ll maintain some of his current friendships, even if he and his friends go in different directions after high school. Talk about meeting new friends down the road while also honoring some of his friendships from the past.

Cognitive Development

By age 18, teens exhibit a lot of adult-like thinking (even though their brains are yet done developing).

They can think abstractly and they’re often future-oriented. They’re able to understand, plan, and pursue long-range goals.

They often show a lot of concern for the future. They may feel overwhelmed at times when people ask them what they’re doing to with their lives.

Many of them are philosophical and idealistic as well. They have a greater capacity to use insight, however.

Speech & Language

Most 18-year-olds speak differently to their peers than they do their family or teachers. They may use a fair amount of slang and they’re usually adept at using social media acronyms.

The teens who read the most are likely to have the most expansive vocabularies. By now, they’re able to communicate like other adults.

Play

Most 18-year-olds enjoy spending time and talking with their friends. They often have similar hobbies and interests as other adults.

Key Milestones

  • Makes future plans
  • Sets long-term goals
  • Able to make their own schedule and plans

Parenting Tip

It’s normal to experience a sense of grief as your child turns into an adult. Make sure you don’t allow the sadness you might experience to burden your child. Make it clear that although it will be a big change for you, you’re also happy that your child will be heading out into the real world.

Other Milestones

Your 18-year-old may be concerned with morality. He may be continuing to evaluate his values and the type of life he wants to live as an adult.

Your teen may also be thinking about his spiritual beliefs. It’s normal to question the beliefs he held during childhood and to consider if he wants to continue practicing a certain religion or continue carrying out certain spiritual activities in adulthood.

When to Be Concerned

Changes in appetite, ongoing body image issues, behavior changes, academic issues, or changes in sleep patterns could be signs your teen is experiencing a mental health issue. Substance abuse issues may also become a problem at this age.

If your concerned about your teen’s development, encourage your child to talk to his doctor. Support his efforts in scheduling an appointment and be willing to go with him to the appointment to talk about any concerns you have.

A Word From Verywell

Even though your child has turned 18, your parenting work is far from over. But, you’ll likely find that your relationship will shift. Instead of being the disciplinarian, you can take on more of a role of mentor and guide.

You’ll likely watch your teen mature a lot in the coming years. Life experience, whether it’s a job, college, or the military, will give your teen the opportunity to sharpen the skills you’ve taught him.

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