I cant say anything for the first two questions since i aint a chick, but for the third one...
Me and my ex had the same thing. In the beggining, while we were both new to eachother, we would play around and stuffs but she would take off her bra/shirt. I think its because she was just shy, maybe the girl you were with was shy as well... Now, i dont know your age, but I would suggest going slow. I went like you did and things went south quickly. Also, communication is the key. Try to talk with her about that. If she shies out, give her time.
But yeah, just dont do anything reckless or it might cost you your head or your friendship with her...
But if i were you i would listen to me anyways, i would rather wait untill someone.... Less crazy... Said anything about that situation... xD
But whatever happens, good luck dude.