system
A chat on subreddit /r/NoStupidQuestions
human
I did gymnastics as a young kid, maybe age 5? But I hated it and dropped out because I didn't like the idea of the instructor being a man and the entire class was young girls wearing leotards that were basically one piece swimming costumes.

I'd love to take it up again as an adult but I don't want to be in a tiny outfit.
gpt
FYI: Adult gymnasts generally wear things like sports bras and shorts because it's comfiest, but you could wear literally anything to class as long as it's not baggy and getting in your way. Many adult gymnasts don't even own a leotard, I bought my first 2 a few years into training. 

I will say that owning leos has made me appreciate why they are the best clothing for the sport. But anything that stays on is totally cool! Go give it a try!

Source: Train at a gym and have been to adult gymnastics camp.