Don't mean to throw cold water on your dreams, however, in most States you can't legally purchase a vehicle at 15. I'll assume that the folks are in agreement with this purchase and will buy the car with your money, and sign the note, you did say you're looking at $8000 and only have $2600.

Have you checked the insurance rates on this car? Beng 15 with a car like the Crossfire it should be expensive, then there's the maintenance costs; ie. oil changes (store bought) can run in excess of $100, tires can cost in excess of $700 and don't get me started on A/C units. You did say 80K + miles on this car, didn't you?

When my step-son went through this, he had neglected to consider the hidden costs to owning a car, insurance, gas, oil, tires, batteries and so on. He tried to sell me on "look it's only $260 per month" Well it's a whole lot more, I knew that and he has learned it.

I do wish you good luck in achieving your goal. Keep us posted to your progress.