It depends do whatever your heart wants to do
Gymnastics is a pretty tough sport! I like competitive cheer though, it comes with a team and friends! Gymnastics I really felt alone, but It was fun! I would make a pros and cons list. It always works for me!
I think you should do all-star cheer (correct term for competitive cheer) because when you do cheer you take gymnastics at you cheer gym but only its just floor gymnastics not bars beam etc.. but all star star cheer if amazing you cant help but crave the feeling you get when you walk on that floor and walking off the floor knowing you hit a perfect routine <3
How old are you?
It all depends on what you want to do when you're older. Do you want to do gymnastics in college?
& what level are you?
If you're young and on a higher level, (past level 6), stay in gymnastics. I quit gymnastics when I was 11 and level 7 and now i cheer and i regret quitting so much.