Different Teenage Development Stages


A little boy wearing a green shirt

Adolescence is the period of transition between childhood and adulthood. It includes some big changes—to the body, and to the way a young person relates to the world.

The many physical, sexual, cognitive, social, and emotional changes that happen during this time can bring anticipation and anxiety for both children and their families. Understanding what to expect at different stages can promote healthy development throughout adolescence and into early adulthood. 

Early Adolescence (Ages 10 to 13)

A man lying on a bed

During this stage, children often start to grow more quickly. They also begin notice other body changes, including hair growth under the arms and near the genitals, breast development in females and enlargement of the testicles in males. They usually start a year or two earlier in girls than boys, and it can be normal for some changes to start as early as age 8 for females and age 9 for males. Many girls may start their period at around age 12, on average 2-3 years after the onset of breast development.

These body changes can inspire curiosity and anxiety in some―especially if they do not know what to expect or what is normal. Some children may also question their gender identity at this time, and the onset of puberty can be a difficult time for transgender children. 

Early adolescents have concrete, black-and-white thinking. Things are either right or wrong, great or terrible, without much room in between.  It is normal at this stage for young people to center their thinking on themselves (called “egocentrism”).  As part of this, preteens and early teens are often self-conscious about their appearance and feel as though they are always being judged by their peers.

Pre-teens feel an increased need for privacy.  They may start to explore ways of being independent from their family. In this process, they may push boundaries and may react strongly if parents or guardians reinforce limits.

Middle Adolescence (Ages 14 to 17)

A little boy sitting at a table eating food

Physical changes from puberty continue during middle adolescence.  Most males will have started their growth spurt, and puberty-related changes continue. They may have some voice cracking, for example, as their voices lower.  Some develop acne. Physical changes may be nearly complete for females, and most girls now have regular periods.

At this age, many teens become interested in romantic and sexual relationships. They may question and explore their sexual identity―which may be stressful if they do not have support from peers, family, or community. Another typical way of exploring sex and sexuality for teens of all genders is self-stimulation, also called masturbation.

Many middle adolescents have more arguments with their parents as they struggle for more independence. They may spend less time with family and more time with friends. They are very concerned about their appearance, and peer pressure may peak at this age.   

Late Adolescents (18-21… and beyond!)

Late adolescents generally have completed physical development and grown to their full adult height. They usually have more impulse control by now and may be better able to gauge risks and rewards accurately. In comparison to middle adolescents, youth in late adolescence might find themselves thinking:

  • “While I do love Paul Rudd movies, I need to study for my final.”
  • “I should wear a condom…even though my girlfriend is on birth control, that’s not 100% in preventing pregnancy.”
  • “Even though marijuana is legal, I’m worried about how it might affect my mood and work/school performance.”

Teens entering early adulthood have a stronger sense of their own individuality now and can identify their own values. They may become more focused on the future and base decisions on their hopes and ideals. Friendships and romantic relationships become more stable. They become more emotionally and physically separated from their family. However, many reestablish an “adult” relationship with their parents, considering them more an equal from whom to ask advice and discuss mature topics with, rather than an authority figure.  

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