Perfect, but not perfect enough for a committment?

I've know my friend for 10 plus years. We recently decided to go on a few dates as more than friends. I feel like I'm falling in love with her. She says she feels the same. She told me that I was everything she could ever ask for in a guy and that she's hoped and prayed that someone like me would come along. But now that I'm here she says she's scared to commit. I've actually been contemplating marrying this woman. Having a family with her and all that jazz. Which if you know me, you'd think I fell and bumped my head because I've always viewed marriage as a complete and utter farce and I've always been scared to have children (she doesn't know that I used to feel that way though. I've never talked to her about relationship stuff until recently and she's never seen my interactions with other wome since her and I have lived a couple of hours away for the better part of the 10 years I've known her.)....but How can I be so perfect to her but not perfect enough to at least be her boyfriend?