Girls generally begin puberty at about 10 to 12 years of age and continue to do so until about 19 years of age, although a few may enter puberty earlier. Puberty is the transition period between childhood and adulthood. Under normal circumstances, girls formally enter puberty at around 10 years of age when their first and second sexual characteristics gradually change, mainly manifested in the gradual maturation of the uterus, vagina and external genital organs, as well as changes in the breasts, body shape, pelvis and other aspects. Breast development is the earliest sign of secondary sexual characteristics, which is the sign of the beginning of puberty. In addition, girls entering puberty have greater physical and psychological changes, and should receive relevant health education, familiarize themselves with sexual knowledge, and develop correct sexual concepts. If there are abnormal symptoms such as early height increase and early sexual development, the patient should seek medical treatment as soon as possible.