The onset of menstruation usually occurs in women who are:

The onset of menstruation, or menarche, typically occurs between the ages of 11 and 16 years. This range reflects normal biological development, as most girls start menstruating around the time of puberty when their bodies undergo significant hormonal changes. The average age for menarche is approximately 12 to 13 years, but it can vary for each individual, which is why a range of 11 to 16 years is considered the standard.

The other age ranges provided do not align with the typical onset of menstruation. Starting menstruation before the age of 11 is considered early, while starting after age 16 may indicate a delay that could require medical evaluation. Understanding this age range is important for recognizing normal pubertal development and providing appropriate health education.