Firstly, here an anatomy picture about a body of a little girl, a teenager girl, and an adult woman. You can see, the little girls don't have a real womanly body figure, they breasts don't grow yet, and their sciatic not wide too. Nowadays it's not generally, but when a girl grown up, her breasts grow too, but she has longer arms and legs, and her body figure is slender, as she has a suddenly big growth. The teenager and the adult part don't have too big differents nowadays. Just some little changing, like the breast and the sciatic be bigger and wider, but it's not always happening.