How can you keep a long distance relationship. We are teenagers (please don't say we're too young because we're 15)?

Maybe try and text each other. Send cute message's, try "Good Morning" or stuff that will keep each other attached. Having dull conversation's will make each other lose interest. Face Time each other, or web cam every so often. Call each other, when you have the time to, and make some plan's to see each other in the future. When you have a long distance relationship, you want to see each other. If you don't, then it's not really a relationship. While you guy's are waiting for the moment you'll see each other, try to get to know each other, for the mean time. Hope this helps! And try to understand if he really like's you, he might be using you for comfort or something :P