What is the normal age for a girl's first menstruation?

Generally, the normal age range for a girl's first menstruation (menarche) is between 11 and 16 years old. A detailed explanation is as follows:

Menarche is an important sign of puberty, indicating the gradual maturation of a girl's reproductive system. This age range can be influenced by multiple factors, including genetics, nutritional status, and living environment. With improvements in living standards and nutrition, there is a trend toward earlier menarche; however, most girls will experience their first period between the ages of 11 and 16. If a girl experiences menarche before the age of 9, it may indicate precocious puberty and should be monitored closely. Conversely, if menarche has not occurred by age 16, it is recommended to seek medical evaluation to rule out potential health issues.

In daily life, parents should regularly monitor a girl's height, weight, and development of secondary sexual characteristics, promptly identifying and addressing any abnormalities. Additionally, girls should be educated about these physiological changes to help them understand and manage this transition without unnecessary fear or anxiety.