It is usually not too early for girls to develop at age 9. Early development in girls usually means the appearance of secondary sexual characteristics before the age of 8, such as breast development, protruding buttocks, and the onset of menstruation. When a girl starts to develop, her body organs will start to change, such as her height and weight will increase rapidly, she will notice a change in her voice, her breasts will start to grow, she will start to develop armpit and pubic hair, her buttocks will become bigger, her pelvis will widen, and she will have a menstrual period. It is normal for girls to start developing at age 9, so don’t worry too much. If your child has any abnormalities during puberty, it is recommended to go to a regular hospital in time and follow the doctor’s instructions, and parents should not give their children drugs without authorization.