My parents hate my (now secret) girlfriend.?

Ok here we go. I met this girl and when i met her she wasn't exactly good. She did bad things and whatever but wanted to change. Me being Christian talked to her and stuff and she was extreamly open to the idea of Christianity. I told my parents and they GOOGLED her... They found an old formspring account with extreamely bad things on it. They told me I wasn't allowed to date her and I even got kicked out for a couple night because of it. (I slept at a playground...) since then she has changed and doesn't do anything bad (consistently we all mess up) but she hasn't messed up seriously. Anyway she changed and it's been 9 months now and we've had a secret relationship for that long. She is 100% Christian now. I have no clue what to do. I know my parents want the best for me but I feel like he is. I wish I could let them see her, for who she is, not her past.