Two things:
1) She's super cute. Thanks for sharing.
2) She has NO IDEA she's super cute. I can relate to your story; I'm married to an
Amazing and Gorgeous Woman who is totally clueless about how amazing and gorgeous as she is.
What it takes is patience, patience, and more patience. You've got to understand that when she looks in the mirror she DOESN'T SEE the same things you see. She sees everything that's wrong with her. She doesn't look at the whole package, or even focus in on the positives the way you and I do.
You're probably overestimating the damage you did with your earlier comment, by the way. She'd set herself up to think she was fat and ugly long before you came along. I'm sure you hurt her feelings (you've apologized, right? and made sure she knew you meant it?), but I'd bet the real damage was long done by the time you got there. And SHE did it, not you.
What there is to do now is love her exactly, precisely the way she is--INCLUDING her self-image issues. LOVE those self-image issues. They're part of her, and they're not going away, though with your support she will get better and better at not listening to them.