I'd say most women have them or will have them by the time they have kids. I know it isn't exactly how we'd like to be, but think about how many great things we have in life and how little a thing like stretch marks really matters. I know how you feel though, it is hard when there is so much pressure to look a certain way that obviously isn't natural. Stretch marks are natural & you are beautiful anyway.
I also liked the suggestion about getting creative with clothing if you feel too self conscious showing too much skin.