Menstruation generally refers to the onset of menstruation. It is usually normal for children to have their first menstrual period at the age of 11, and parents should be well informed about this. Most girls have their first menstrual period between the ages of 13 and 14 years old, and with adequate nutritional intake, some children may have their first menstrual period as early as 11 years old or as late as 16 years old. Therefore, it is normal for an 11 year old to have her first menstrual period. The early onset of menstruation is mainly related to genetic factors, nutritional factors, weight changes, etc. If there are no other abnormalities, there is no need to worry too much. The onset of menstruation is a normal physiological phenomenon. As a parent, you should set up the correct concept of menstruation, how to use sanitary napkins, and the accompanying symptoms of menstruation for your child, so as to avoid any psychological burden on him/her. At the same time, the onset of menstruation indicates that the ovaries are well developed, so parents should also instruct their children to pay attention to the protection of personal safety. If an 11-year-old child has other abnormal symptoms in addition to menstruation, parents should take the child to a doctor for examination so that the specific situation can be clarified and treatment measures can be taken according to the doctor’s instructions.