blue.and.green.eyes: Welcome to the forums. What a great question you're asking. I think it's great that you and she are talking openly about these things.
Our society sends young people a lot of mixed messages: "Be pure, wait until marriage, be a virgin on your wedding day; but there's something wrong with you if you aren't having sex."
There is absolutely nothing wrong with what you believe or your paradigms. Sexual freedom means the right to make your own choices. It doesn't mean that you have to jump into bed with someone because that's what they do on TV.
There are a lot of positives to the old values of abstinence before marriage. No method of birth control, even surgical sterilization, is 100%. All methods have a failure rate. Also, I know it feels like you're meant for each other, but there is no guarantee you and she will end up married. I had my first sexual experience with a girl I was engaged to and then we ended up breaking up. It was important for me to only have one sexual partner for a lifetime, and I was very sad when I knew that that could never happen. There are a lot of advantages to waiting.
If you and she choose to proceed with sexual activity, I'm glad that you and she have thought this totally through. it's important to talk about the good and the bad things that can happen. Ultimately, it this choice belongs to you and she. This is a conversation that only you and she can have. I hope I've given you some things to consider.
Best wishes for the two of you.