She won't sleep with me until we are married. How to proceed?

I'm in my 20's. A few days back she let me kiss her. I kissed her cheeks, her lips, her neck and shoulders. No where else. She gave me a big hug and thanked me. I find her absolutely ravishing and irarisistable, but i am a gentleman. A few days later I met her for a walk, and just talked with her. She told me that she always dreamed of a nice wedding and wanted to do it in a pretty dress with a pretty cake. I asked her what she would say if I proposed to her and she said, with tears in her eyes, that she can't imagine living with someone else but me.<br><br>So I did it, I brought her to a pretty park and asked her with flowers. I was so nervous and she said yes and we cried together. We talked about our wedding and how we wanted to marry. She told me that she wants to work as long as possible and marry as soon as possible after finishing her last exam. She told me that she wants to be a virgin until marriage. I said that she was acting very mature and responsible for someone her age. I'm not sure how much she knows about sex, so I told her that we need to go to a doctor to get advice if we were to do it. She said that she could do it the "classical" way, and i said that the "classical" way and to do it properly with a doctor were the same things. And that they were illegal without a doctor. I asked her how old she was, and she said 16. I'm 26 myself. I'm really conflicted, because marrying her may be illegal. Other than that i have no other concerns about marrying her. She is the perfect girl for me. What should I do?