Hi. To me, if you want to buy a car at 18, you should first decide what kind of car you want to buy. Then, I think you should rent that car for a few days or even weeks and try to drive it to make sure you like everything about the car. For that you should go to VAN Rental fort worth.
You will be able to rent one of thousands of great vehicles and then decide if it is worth it to you.
I hope I helped you.