Boobs

Ok so I'm 13 and have pretty big boobs (I'm a size 38dd) anyways it runs in the family. So I struggle with self confidence and am scared to show how big my boobs are to anyone. Last year I wore a sweater every single day of school and when people asked why I always said I was cold. I hate big boobs especially since I'm probably not even done growing. For some reason my boobs are SUPER saggy. I went bra shopping today and I see all these beautiful women with cleavage and I look at myself and I don't have any cleavage. So I was wondering if anyone has some tricks for big boobs please tell me.