It is medically normal for a girl to menstruate at the age of 10. Because precocious puberty is medically defined as the onset of menstruation before the age of 10, it is normal to have menstruation at age 10 or later. However, if menstruation occurs too early and the base height is low, it may affect the girl’s mental health and eventual height development. Therefore, if a girl has her period at age 10 and is under 1.5 meters tall, or even only about 1.4 meters tall, she should seek medical attention as soon as possible. According to the doctor’s judgment, it is possible to handle the method of height increase to promote the eventual height growth. Therefore, although the onset of menstruation at age 10 is within the normal range for girls, parents need to make a judgment based on the base height at that time. If the girl’s height is still below 1.5m, the final adult height may only be 1.55m or below 1.6m, which may cause greater problems for future life, study and work. Parents need to pay attention to this and seek professional medical attention and intervention from doctors as soon as possible.