Say that I want to become an Animagus, and am really hoping to be a certain animal (say, a stag). I study a whole bunch and manage to perfect the technique. Do I get to pick the animal I wind up as, so that I wind up being a stag like I want? Or is it something where I just find out what I turn into (and if I wind up as a dung beetle, tough luck)?
This is not a duplicate of Can an Animagus take the form of any animal? because that question is about which animals an Animagus can potentially transform into. Mine is about if I can decide which potential animal I wind up being.