Not to sound preachy or anything, but 13 is way too young to go on the pill. I went on the pill when I was 16 and that was because my menstrual cramps were unbearable. Your body is still young and developing and you shouldn't put prescription drugs into your body any longer than you absolutely have to. All prescription drugs come with some risk, and the longer you take them, the more chance you have of developing a problem. And there should not be a "just in case". When you are ready to have sex, it should be something that is thoroughly thought out. I lost my virginity when I was 16, almost 17, and I honestly wish I would have waited until I was older. In my opinion, I don't really feel like I was mature enough to appreciate the experience. I can't even imagine how I would have felt about it at 13. I am sure you practically just started your period- sex is not even something you should be considering. My advice? Wait until you're at least old enough to drive a car until you think about having sex. Most older teens, let alone a 13 year old, cannot accept the responsibilities and consequences of sex.