It depends on the relationship. If you're just kissing and cuddling on the couch to watch movies, going out for dinner together, etc. then it's no harm. However, if you're doing anything sexual it's not good at all. He could be sent to prison, and if he's pressured you that makes it even worse. It's possible to make that connection at those ages, but most people do not act on them until the younger is of age. It's something to think about. One big thing you need to think about is whether or not your parents would approve.