I'm 14, 5"5, around 137, and I'm wearing a 32 DD bra. When we got my breasts measured and it turned out im a 32 DD (while the last year I had been a 34 C cup), my mom almost seemed mad at me for it... she is somewhere in the DDD's, so I guess maybe its genetic, but my breats are bigger then almost all the other girls in my grade, so I dont know if I'm "ahead of schedule" or however you say it, but it kinda worried me.