I would suggest waiting a while. Once you guys get out of high school a lot of things could change. If anything you guys could get engaged but make it a long engagement and don't get married until at least 18. You guys have plenty of time and it is always better to break off an engagement rather than get divorced. Just give it some time.
It would be kind of cute... living in their parents home for two years, then probably having to live in it some more. Then you guys will probably get sick of each other, and bitter fighting will ensue.
but salt, isnt that part of all true love?.......................lol