This is some good basic info on how to fix your hair for gymnastics.
This girl is really good at braiding her own hair – not something that everyone can do well. Maybe she has practiced a lot.
In any case, she’s got some good ideas for hair styles that you can wear during gymnastics. They may take some practice. Maybe you and a friend can practice on each other. And of course, if your hair is shorter than hers, you’ll have to improvise.