Is it normal to get stretch marks on your thighs during the second trimester of pregnancy?

I am now 19 weeks pregnant. I have been putting sretch mark cream on my belly since about 10 weeks. I already have a big belly to be 19 weeks, and don't have stretch marks on my belly! I never thought to put some on my thighs....I was always average weight for my age and height so it kinda bothers me that I have them! I know it's normal to get vericose veins, but is it normal to get stretch marks at 19 weeks?