Do you think he really loves me?

My boyfriend is 15 and I am 13. He says he loves me and always wants to be with me, forever. He says that i am the most beautiful girl he knows, even when im in sweats with no make up. He says he wants to marry me, and i want to marry him. We also agree that neither one of us want to have until we are married, and we openly discussed this fact. He never goes any further than a simple kiss --that goes as far as touching also. And when we are in public, he only kisses mw on the cheek, as both of us are against PDA. Our families are friends through roller derby and eachothers parents like their kids boyfriend or girlfriend (my family likes him, his family likes me) so we are good there. We are the same religion and have friends in common. I love him with all my heart. I know some will say that i am too young to know and understand what love is, but what is age but a number? He likes it when i dress modestly as opposed to those mini skirt half shirt outfits as well. What do you think, do we love eachother to stand a chance at marriage?