Why do i keep bleeding when my boyfriend barely puts it in? and when we do have sex i'm not on my period at the time.

That's not good.: Maybe because you're 15 years old and your body is not ready for sexual intercourse. Or you may have a large and or thick hymen or it could be something else. Bottom line: you are not supposed to bleed every time you have sex, so you need to go get checked: planned parenthood or a woman's clinic can help you. Also, please make sure you're on effective birth control and using condoms........