I'm thinking about picking up ballet :p , not in a competitive or performance sense, but to improve my balance, flexibility, and jumping ability -- as well as improve my ankle strength.

Does anyone have any experiences with adult ballet?

I'm an 18 year old male, BTW.

I'm thinking about picking up ballet :p , not in a competitive or performance sense, but to improve my balance, flexibility, and jumping ability -- as well as improve my ankle strength.

Does anyone have any experiences with adult ballet?

I'm an 18 year old male, BTW.

Actually, yes. I did ballet from age 10-13. Not very adult though, I know.
But if you already train as a gymnast, I guess your balance, flexibility and jumping ability are already very decent so I don't quite see the need for picking up ballet in order to improve those qualities.
However, I do believe that ballet will improve your grace and make your gymnast exercises more esthetic.

Thanks for the planche-info by the way! :tu: