Well... If it was me in this situation I'd probably say "lol, Quack" and try to forget what just happened and wait until I was old enough to drive, get a job, be able to pay my own gas, manage my finances and life, etc.
I don't really see the point in a middleschool "relationship" but maybe I'm just weird. I would say just stay friends and think about dating stuff when you're older but feel free to attack for my somewhat different beliefs : )
I’d probably say to wait it out a bit longer, and talk to that guy