Considering shaving (girls)?

Ok well im 13 in 8th grade and im starting swimming in pe and im kinda nervous bout dressing out COMPLETELY???? im kinda concerned if i shud shave my down under or not or just trim short or what? I shave my armpits and legs and sometimes my arms. So i need help because i dont want it to stick out while im swimming(ewww) so do i just trim or shave? plz helpp???