How are you planning to pay for the truck? You can't sell a car you don't own. You have to pay it off immediately to sell it. With your age and low credit history you'll likely be unable to get any kind of loan for the truck. If you do, the interest rate would be astronomical. You'll end up paying 25K+ for a 12K truck.
...and hells no. That's a 10-12K truck... tops, assuming it's as pretty as the pictures. It has power nothing, drum brakes, straight 6, and no air. To put it in "mustang terms" he wants V8 fastback money for a six cylinder coupe.
Get the car SOLD. I'm assuming you'll only break even, so no real money to spend? Buy a 1-2K beater, drive it for a year. You'll be amazed at how much money you can save with no payments and much lower insurance. And the great thing about a beater is that in a year or two... you can sell it again for what you paid for it.
I told you my story already... I drove two different $400 1986 Toyota truck for like 7 years. Killed the motor on first one, plus it was a rusted to death NY truck, bought a decent rust free South Carolina 2nd truck, with a motor from a 3rd and built one decent truck I drove to Clemson for 5 years. I still got ladies. You know a girl likes you when it's 104* out, you have no A/C and she wants to go for a ride in your rusty pile of crap... those are the good ones
...and another tip on life... if you have to impress a girl with that car to get her to go out with you... you'll NEVER have money, ever... again...