She does look younger than 15 in some pics, its just that in this pic shes wearing skinny jeans, heels, and her hair is done up. I think her outfit definitely adds a few years to her age.
Do you realize the part she will be playing in her next film? She's playing the basass front woman for The Runaways Cherie Currie. She can't tone it down, he has to own this part for it to be belivable. Very cute jeans!