Most Helpful Guy
I would tell him, so that yes once you're at least sixteen or seventeen (depending on where you live) you guys can date if both of you are still interested. I don't think there's anything wrong with the ages as is personally, but the law disagrees sometimes for some dumbass reason.
Most Helpful Girl
Yes you should tell him. No matter how mature you think you are, you are still a teenager. He may not want to flirt or talk like that with a child.