Since this topic has come up again ....
Dvora Meyers published a very good article during the Olympics arguing for the end of the teen gymnast in women's gymnastics. In the article, she reviews the history of women's gymnastics, how teen gymnasts became the norm, and how the sport is now moving away from this. I do find it very interesting that women's gymnastics currently is seeing a resurgence of older, more mature competitors in their 20s and longer careers--developments that seem to be generally celebrated and appreciated among fans. Yet women's skating is moving in the opposite direction, toward younger champions and shorter careers.
Girls in gymnastics start very young and specialize very early, but that wasn’t always the case.
fivethirtyeight.com