yolly - i got my first stretch marks on my tummy at 34 weeks (just under two weeks ago) and now have about 15 of them there!! they seem to breed whenever i take my eye off them!!
they have been the cause of a lot of angst for me as i'm feeling really frumpy, and so out of touch with all of my friends (who are childless, super skinny and stretch-mark free)... i know that at the end of the day i'll have a little baby to bring me so much happiness and i won't care too much about the stretch marks, but it's still very difficult to handle when you can see your body literally falling apart around you!!
i've also had the thoughts "i wish the baby would come so that i don't get any more stretch marks and don't put on any more weight" - it's very normal, and i'm still hoping it happens - imagine how many stretch marks i could have if i go to 42 weeks - aaaghhh!!! hope that baby is nicely cooked and comes out of her own accord soon, but if she doesn't then i'm sure i'll look back in years and laugh at how worked up i got over the stretch marks...