The time during your teens when you become sexually mature is called puberty. It is a physical change that usually happens between ages 10 and 14 for girls and ages 12 and 16 for boys.

Some changes occur in both boys and girls, including

• Growing taller
• Weighing more
• Acne
• Growing underarm and pubic hair

In addition, girls develop breasts and begin their periods. Boys become more muscular, their voices deepen, and their penises and testicles become larger. You might also notice changes in the way you think and feel.