Girls develop some breast tissue under their nipples during puberty. Girls’ breasts continue to develop into all different shapes and sizes and sometimes one breast is bigger than the other. No matter their shape or size, girls’ breasts all work in a similar way to produce milk if she has a baby. Girls might choose to wear a crop-top or bra to support their breasts.
Breasts develop at different ages for different girls, so don’t worry if your breasts develop before or after someone else’s.