Normal people usually stop growing around the age of 20 when puberty ends, but it varies from person to person, and the time at which boys and girls stop growing is also different. Boys generally stop developing as late as around 24 years of age. Boys begin to develop at 13 to 14 years old, and then grow rapidly, growing 9 to 12 cm per year. among boys, some stop developing at 14 years old, and some stop developing at 25 years old. This is related to genetics, nutrition, sports and other factors. Girls usually stop developing at the age of 18 to 20. Girls usually start the initiation of puberty at the age of 8 to 12, have their first menstruation at the age of 12 to 14; at the age of 16 to 18, their breasts are close to those of an adult; and at the age of 18 to 20, the ovaries are more mature. Usually, girls’ bones close earlier, so adult girls are shorter than boys.