Physical Development, Ages 15 to 18 Years

By age 15, most girls have had their first menstrual period and have completed the rapid growth spurt that usually occurs during puberty. After the first period, teenage girls grow 1.5 in. (3.8 cm) to 3 in. (7.6 cm) on average. Other early changes of puberty, such as the growth of pubic hair and breasts,...