No offense, but you should definitely figure this out before you invest in a money pit like a new car.
I understand the temptation to get something you've always wanted when you feel like you have the money. I'm sure everybody here knows that feeling. The key is to resist the temptation and do the smart thing with your money.
It's tough, but it's part of growing up. I'm not trying to be condescending, but you are young and if you learn how to handle your money responsibly now, it will pay you HUGE dividends later. I'm still cleaning up messes I made with my finances from years ago. Finally, I've started to get things straightened up, but because of the past I've got a lot of catching up to do.
Don't make that mistake now, or you'll continue on the same path until something shakes your world.