Your breasts start growing when you begin puberty. During puberty the hormone levels in your body change. This causes your breasts to develop and your periods to start. It takes different people different amounts of time to develop breasts. The age when you start to develop does not have an effect on the final size of your breasts. For example, if you develop later than most girls, this doesn’t mean that you will have smaller breasts than most girls.
Women’s breasts come in all shapes and sizes. There is no perfect shape or size for breasts. Normal breasts can be large or small, smooth or lumpy, and light or dark. Heredity is the most important factor in determining breast shape and size. No creams, special exercises, or clothing will permanently change your breast size, however, certain bra styles with padding can enhance the size of your breasts. Your breasts may change with weight loss or gain or after a pregnancy, but for the most part the size of your breasts stays the same once you’ve finished puberty. Also, breast size has no effect on whether a woman will be able to breastfeed her baby.