Here's the best thing I ever did re: credit--
-- go to
www.myfico.com and learn about the mechanics of credit, how to establish it, improve it, resuscitate it, and maintain it.
Before you begin lowering your credit score by applying for a bunch of credit cards (and yes, credit card applications DO lower your scores, as does the application for a car loan) find out where you stand-- buy the
FICO Deluxe report-- it's instant, and gives you a complete history from all three major agencies-- along with about a million other cool tools and stuff.
The site is invaluable to me-- I don't care if you can get your score for free somewhere-- it won't show you **** except basic info, which you can't do much with anyway-- this site gives you TONS-- and is worth every penny.
Cheers--
PS-- If you are making enough money at nineteen years old to spend $6-800 a month or more for a car, congratulations--- I'm really impressed. (taking into account the interest rate you'll probably get, even if your parents have golden credit, and the very high insurance cost you will unavoidably have because of being in the highest insurance risk category, I think this monthly cost is reasonable for you to expect)
Don't take it personally when people don't take you seriously-- if you are in an unusually affluent household/job situation, then that's great-- but there are a million teenagers who talk about buying expensive cars, so you gotta admit that it's understandable that there is a common dismissal of such things, since 99% of kids your age can't really handle that kind of expense and people know that.
Best of luck, seriously, and make sure to check out that site-- it taught me a LOT!