Breast development usually stops around the age of 16-18, and depending on one’s physical condition, it may occur a year or so earlier or a year or so later. Breast development usually starts when girls are 10-12 years old, with the appearance of areolas and nipples on the breasts and the enlargement of the breasts, and it usually stops when they are about 16-18 years old. Poor nutrition, excessive estrogen in food intake or medication that affects estrogen may cause breast development to advance by about a year or be pushed back by about a year. Breast corset should be avoided during breast development, which restricts the growth of milk ducts and glandular follicles. Corset can also cause nipple inversion, which is formed when the nipple, which is supposed to grow outward, is pressurized and plunged into the breast. You should do chest exercise properly, avoid chest injury, reduce breast pressure, and take good hygienic precautions. Women with abnormal breast development should go to the hospital in time and be treated actively under the doctor’s advice.