When Do Periods Start Understanding a Girls First Menstrual Cycle The first menstrual period also known as menarche is an important milestone in a girls life. It marks the beginning of reproductive maturity and is a natural part of growing up. Many parents and adolescents worry about when periods should start and what is considered normal. What Is the Average Age for the First Period Most girls experience their first period around the age of 12 years. However this is only an average. It is completely normal for periods to begin anytime between 8 and 16 years of age. Why Can the Age Vary Several factors can affect when menstruation begins. These include genetics body weight and nutrition physical activity levels stress and environmental factors and overall hormonal health. Early or late onset does not automatically mean there is a problem. What Is Considered Early or Delayed Periods starting before 8 years are considered early. No periods by 16 years are considered delayed. In these cases it is advisable to consult a gynecologist to rule out hormonal or medical causes. What Should Parents and Girls Know The first few cycles may be irregular which is normal. Mild cramps back pain or mood changes may occur. Proper menstrual hygiene is essential. Open conversations reduce fear and embarrassment. When Should You See a Doctor A gynecologist should be consulted if periods start very early or very late if there is severe pain or heavy bleeding if cycles remain irregular for several years or if there are concerns about growth or development. Final Thoughts Menstruation is a sign of a healthy developing body. There is no right or wrong age to start periods within the normal range. Awareness acceptance and timely medical guidance help ensure a positive and healthy transition into adolescence.