It isn't though. Most of the female gymnasts in Rio 2016 were over 18. And most of the medalist there were over 18 as well.I'd honestly like this to be what we see in the Olympics. The fact that the peak prime of a women's gymnast is 12-14 with a per-pubescent body hasn't sat right for me even before all we've learned in the last year.
http://www.excellesports.com/news/gymnastics-age-of-olympics-older/