First off just be yourself, you shouldnt change for anyone. I dont want to be a downer or anything but also dont get too caught up with this guy, like dont make him your world, you are still really young and have alot ahead of you. I was 15 when i met my now husband, we had a baby when i was 18 and then got married when i was 19. I love him alot dont get me wrong, but sometimes i just wish that i had lived a little more before i got really serious with him. But anyways just be yourself and if he really likes you then that is all that should matter.