Marrying highschool sweetheart?

Is it possible to marry your highschool sweetheart? My boyfriend and I are only freshmen in highschool, but I love him a lot and I never want to lose him. He's not only my boyfriend, but my bestfriend. I know what you're thinking,"oh, you're too young for forever blah blah," but I don't feel that way.. I feel as if he really is the one and I hope to God he is. We've had talks about our future together, and we have even promised to never leave one another. I know promises can be broken, but I trust him and he trusts me..so if neither of us leave and the love between us just grows during the next right years..do you think we will make our relationship last forever and that we'll get married one day? Any tips on how to make the love last?