What do you mean she doesn't have permission? How old is she?
If you don't know where she stands with God, ask her. I know it doesn't help you now, but this is something we really need to have answered before we enter into a relationship with someone.
I know you say you already have feelings for her, but if she doesn't know God and isn't interested in knowing Him, it will only become more dangerous and hurtful for both of you down the road.