Sounds like me OP. My first stint at college right out of HS didnt go so well, I got blown away by the partying, freedom, etc. Ended up leaving school at the age of 20 with a horrid 1.1 GPA and found a job in IT which paid super well so I ditched the idea of school altogether.
Then, at the age of 24 I was like damn I should finish up. I applied to a different school, transferred any credits I could, and finished my last 70 odd credits in 2 years. The second time around I was so focused, dedicated, and on the ball. I was watching all of the "kids" doing the same crap I was doing when I was younger, and I tried to advise some of them to get their shit together, but I guess its just something you have to learn for yourself.
Anyway, I finished my Engineering degree with a robust 3.9GPA and I couldnt be happier at the decision of quitting that job and going back to school FT... Even though while I was in school 9/11 happened and the IT market crashed by the time I graduated lol.
Good luck to you OP. Im sure you will do fine.