So I'm 27 years old and when I was 18 I went through credit cards like crazy, never paid on them, bought a car, had it repoed, and just did not care. Now I know that all of that was irresponsible and I want to start over or rebuild my credit or something. What should I do and where do I start?

If you want to rebuild your credit you should get a credit report and find out who you owe money to so you can pay them off. Contact them and tell ask them if you can make payment arrangements with them. You will have to pay for the car that was repossessed though.

Chances are your credit is already very bad if you haven't been paying for your credit cards or for the car. You are still responsible for the car when it is repossessed.

Your best bet may be to contact a local bankruptcy trustee after having a credit report done and file for bankruptcy.