ANDY'S ANSWER: Just because your friend has started her period doesn't mean that you will start yours. 10 is on the early side for starting your period and the average age is usually 12 or 13. Your body will give you its own signs of when it's starting puberty. If your breasts have started to growing, your period is usually about 2 years behind. You will also notice a clear vaginal discharge between 2 years and 6 months before your period starts. In any case, it never hurts to carry a panty liner with you at all times in your purse.