i feel like, a brony is anypony who wishes to think of themselves as one. i have pony things, and i am confident enough to not hide them. but, i do not think of myself as a brony, necessarily. why, i just like to post ponies and i love the show.
perhaps, in the eyes of others, i am a brony. i am okay, if that is how they see it. i do not think too much of who should or should not be, or is, or is not, a brony. i think... all ponies under Celestia's sun are sisters.