Is it normal for a 13 year old female whos 5'2 to have 34dd even though shes not overweight or obese?

It happens. The eventual breast size of any female depends on an interaction of their hormones and the receptor cells in their breast. They could end up as a bump on a pancake or a watermelon. These are managed as best they can with professional bra selection. After they finish their growth phase, some elect reduction when back issues become a quality-of-life problem