Good of bad?

Not really. If needed, they can always give u a wig (there are some that look REALLY realistic, for both theatre and for film.) If it was ABSOLUTELY necessary, they may ask u to cut it, but they probably won't. So I wouldn't worry about it :)

hm....in some ways i think it could make it harder, in the case that your character is completely average and your hair would mess that up....but i also thnk your hair could be a big help to you. it might help u to make a lasting impression and it might help set u apart from the rest.

Um, I don't really get what u mean but I think long hair could be a disadvantage as it could get in your way, easily get caught in things.
But if that's how u want your hair then keep it, just figure a way to keep it out your face, like in a bun of something like that.

it completely depends on the type of parts u want and how the director envisions the character. the only way it would be a disadvantage is if u completely refuse to cut your hair for a part.