There is no set age at which puberty begins or ends, but women are typically fully developed by their late teens, according to TeenHealthSource. Girls can begin to develop as early as 8 years old or as late as 14.
The awkward puberty phase affects boys and girls in different ways, but the experience of changing bodies and new hormonal shifts are something they share. The first sign that a girl is beginning to develop is usually breast growth, which is followed shortly by her first period. Although puberty happens to most people during their teens, the human body in general can continue to grow throughout the early 20s.