The sign of girls entering puberty is not divided by age, but by the development of sex organs, girls appear secondary sexual characteristics development suggests puberty start refers to the beginning of growing breasts, the general age of growing breasts is 11 years old, that is to say, suggests the beginning of puberty. At present, due to changes in the living environment and changes in dietary factors and diseases, many girls enter puberty early, and some will enter puberty before the age of 8. Entering puberty before the age of 8 suggests precocious puberty, and growing breasts during the age of 8-11 years suggests early sexual development, and whether or not to enter puberty is based on the level of estrogen in the body caused by the development of the sex organs as a symbol.