Everybody develops, their own version of what loves means to them and you are a bit too young, to actually understand what that could be even to you. But I can tell you what love means to me... Love is when you look at your SO and you smile everytime you see them, when you discover new things about a that person and cherish them in your mind as some special group of information, that you don't want to forget. It's when you can be truly yourself around a person and trust them with your life. When you feel almighty and unstoppable, just because you have that special person beside you. And much more. From physical point of view, it works the same for everyone. It's like a drug. When you have that special person in your life and share experiences with them, your hormones of happiness increase to maximum. That's why most people can't get trought a break up very easily, it's like taking some hard drug, from them, knowing they will never going have a chance to taste that drug again.