Christ, you're just a 14 yr old KID!
They're probably gonna go real easy on you.
I thought it was a really kiddish solution to run away from your truck (since any idiot cop can just trace the license back to your home..) and the cops will probably figure that out and think you were just really scared and paranoid (which you were) and out of pure fear ran away.

By the time you're half finished with high school you're gonna look back and realize how funny it was when you hit and ran the fuck outta there. I'll be surprised if it goes on your permanent record.