Beauty is in the eyes of the beholder my friend. I am not belittling the value, as I am sure she is quite the beauty, and that shouldn't have much to do with you at all, looks are only a small portion of the game, you I'm sure have just as much charm as the next. You do however have to appreciate the skepticism, it's to be expected.
The only real thing that matters is that she finds you beautiful and you find her beautiful. - Appreciate the beauty in THAT and you'll be just fine mate, after that it doesn't matter what others think. Keep it up purely for yourselves.