I really hate it when everyone makes the process to becoming an Animagus fun. I mean would you really want to have a mandrake leaf in your mouth for a whole month? Not to mention the fact that if the process goes wrong it could end in disaster. And no you cannot choose your Animagus form so please stop doing that too as it is incorrect. Becoming an Animagus is much much more than saying a spell and drinking a potion.