The development of the female breast begins after puberty, starting around the age of 12-13 and continues to develop until around the age of 16-18. Due to the influence of various factors, some girls may start to develop their mammary glands around the age of 10 and stop developing them after the end of puberty development. Therefore, during puberty, try to pay attention to a reasonable nutritious diet, eat more fresh vegetables, fruits and high-protein foods to help promote the development of the body. At the same time, ensure that you get enough sleep and do not stay up late, and pay more attention to exercise and exercise. The second development of the mammary gland occurs after pregnancy, but this development will return to normal after the lactation period, which is a temporary breast development. The actual fact is that you will be able to avoid being irritable and often angry, as your mood has a direct impact on your breast.