Nine year old girls will generally still grow after breast development. The development of breasts merely indicates that the child has entered puberty, and the epiphysis of a nine-year-old girl is generally not yet closed at this time, and she can generally grow taller. Nine-year-old girls at this age, the body’s secondary sexual characteristics will slowly manifest, such as breast slight swelling, nipple areola bulging, breast chassis enlargement, etc., this is a very normal physiological phenomenon, and generally will not affect the development of height. Height depends mainly on the degree of epiphyseal closure. A girl’s epiphysis will close at the age of 18 and her height will stop growing. If a nine-year-old girl’s height grows slowly, X-rays can be used to determine if there is premature epiphyseal closure. If an adolescent girl is petite, she should eat more calcium-rich foods and also pay attention to the nutritional balance in her diet.