Puberty is the developmental phase during which a child's body transitions into adulthood, marked by physical, hormonal, and emotional changes. Typically occurring between ages 9 and 16, puberty involves the maturation of the reproductive system and the development of secondary sexual characteristics. For girls, it includes the onset of menstruation, breast development, and changes in body shape. Boys experience growth in testicular size, facial hair growth, and deepening of the voice. Puberty also affects mood and emotions, as hormonal changes can lead to mood swings and increased self-awareness. This period is a crucial time for growth and development, setting the stage for adulthood.

A period, also known as menstruation, is a natural process in the female reproductive cycle where the body sheds the lining of the uterus. This typically occurs about once a month and lasts between 3 to 7 days. During a period, blood and tissue from the uterine lining are expelled through the vagina. Menstruation is a sign of a healthy reproductive system and is a normal part of the menstrual cycle, which is regulated by hormonal changes in the body. The cycle begins at puberty and continues until menopause, marking a significant aspect of reproductive health and fertility.

Everybody is different, but periods usually start somewhere between the ages of 10-14, and about 50% of girls will start their period by the age of 12. Don’t worry if you start your period earlier or later than your friends—it’s totally normal!

Most girls and women find that periods last for about 5-7 days, and that they get their period approximately once a month. After a couple of years of having your period, your body will settle into a pattern that’s unique to you, and you'll be familiar with how many days of bleeding to expect. If you notice that you don’t get your period very often, or if it lasts for longer than 7 days, it might be a good idea to check in with your doctor.