I don't have these booties, but have you also read the reviews at Nordie's? I like reading Nordie's reviews because I think that the people who shop at Nordie's are maybe more clothes savvy than Amazon shoppers. Here is the link:
http://shop.nordstrom.com/s/so.....ot/3196399
I see that the web page says right away that they run small and that you should order half a size up. In my limited experience, those recommendations are pretty accurate.