Every girl is different. The average age is about 12, some girls get their first period as early as 9 and some may get it as late as 16. Chances are you will get your first period at around the same age as your mom.

It's impossible to predict the exact time, but your body will send signals that your first period is about to arrive. You may notice that your breasts are developing and pubic hair will start to grow. You will start to see hair under your arms.

You are getting close to your first period when you notice a discharge coming from your vagina. The discharge may look clear or white in color, and it may be slightly sticky or gooey. This is the time to be prepared by carrying a pad and an extra pair of undies in your purse or backpack.

If you are at school and completely unprepared for your first period, don't panic, many girls have been in that situation before. You can go to the bathroom and make a temporary pad using toilet paper or paper towels. If your pants are stained already, you can wrap a sweater or jacket around your waist to cover them. If you don't have a sweater or jacket, ask your best friends to borrow hers. She may also have a pad that you can borrow.

Call home and have your mom pick you up as soon as possible. Remember every woman has periods and it's no big deal if someone knows that you had your first period.

Lots of girls experience cramps before or during their periods.

During your menstrual period, your uterus contracts to help expel its lining. Hormone-like substances (prostaglandins) involved in pain and inflammation trigger the uterine muscle contractions. Higher levels of prostaglandins are associated with more-severe menstrual cramps.

Severe menstrual cramps may also be caused by fibroids, endometriosis or other conditions. It's advisable to consult a doctor when your cramps are very strong.