I have a suggestion for you. Well, two really.
1. Why in the world are you having sex when you are just a baby? You aren't even driving yet! You think you 'luuuuuve" this boy? Ha. Odds aren't you will not marry him. You will not be together this time next year. Honestly, believe me. Believe us 'older' women in this room...We know. Personal experience. Ever hear this saying "why buy the cow, when you get the milk for free?" yeah, uh....Read it again, think about it. Have a little bit more respecet for yourself than that. 15...That's insane.
2. If you absolutely, positively must have sex, which I highly dought, you should try this thing we like to call a condom. It prevents a lot of things, namely one, babies. If you don't want a baby, use a condom. Use something. And don't use the 'pull out method' which is the dumbest method ever thought up. It will still get you pregnant.
Be good to yourself, have some respect, you will honestly regret your sex decision making when you get older.