Girls usually start to develop during puberty, and the age at which they begin to develop is from 8 to 13 years old, with the average being around 11 years old. As the female body develops, it will show a sudden increase in height, the development of secondary sexual characteristics, the maturation of the reproductive organs and other manifestations, and will gradually have ovulation and produce regular menstruation, the development of girls is usually around 8 to 13 years old, the average age of 11 years old. The average age is 11 years old. However, each person’s specific situation is different and is affected by genetics, environment and diet and exercise. When women are developing, they should learn the health care knowledge of puberty, and if there are any physical symptoms, they should go to the hospital in time, complete the relevant examinations under the guidance of the doctor, and carry out regular treatment to promote the development of the body.