It sounds like you're both being very mature about it. You showed a lot of respect for her and yourself as well. Its cool that she wants to talk to her mom about birth control, that just makes things better in the long run. I'm not sure how forward thinking both your parents are, but if you sit them down (hers and yours) and discuss things, you may be suprised at how cool they are. Some parents allow their kids girlfriend or boyfriend stay over, they feel comfortable since they know they are being safe.
I'm sure it won't be the most easy or comfortable conversation to have, but it might be a good thing to do.
Oh, and good job having a condom around even though you had planned on waiting.
