Hey, we all live and learn. I'm (gulp!) 30 now and I've made bad financial in the past because my desire for something was so strong it overwhelmed rational thought. Unfortunately these are tough lessons to learn because it ends up not just screwing you short-term but possibly long-term as well. Whatever you do don't let your credit get a bad mark on it! It WILL come up later!
I've never owned a car I couldn't afford though. There are kids here who are 17 yrs. old who have a car payment and are in 18 grand worth of debt. All at the age of 17! Yikes! That's no place for a person of that age to be unless they have a really nice trust fund to live off of or happen to be really smart or lucky and have a good paying job (and I don't mean $10 an hr. as an part-time anything). It's hard to swallow, but if you're young and still going to school (meaning you only have some kind of part-time job) you really have no business owning a brand new car unless someone is helping you with the payments or you have been given the car as a gift or you have paid for the car in one lump sum. And shame on those car dealers that make those deals knowing that some kid working part-time in the fast-food industry (no offense) will never really be able to afford the payments. They make it sound so do-able on paper but they never take into account that you buy stuff like books and drinks and burgers and movie tickets. Remember, they make their money whether your car gets repoed or not. It's all about living within your means (something I had to learn the hard way). If you make $15k a year don't buy a $20k car! Save up $3000 instead and buy some used car to get you from point A to point B. Go to school get a piece of paper that says you're worth some money (more than you were when you were in school) and get a good job that pays you what you're worth. Then go buy that $20k or more car and enjoy! Don't forget to bring that fat down payment and your good credit with you!