I lived at home until I was 23 when I bought my house. I had planned on moving out when I was 18 also, but I chose to go to the local community college about 20 min from home so I just stayed at home. I had it gooooooooooood!!! No rent no car payment no college payment!!! I was/am very very very very lucky. And I have wonderfully awesome parents. I had no reason TO leave!
I got thru college, and got my job which is where I still work. I was only part time then so I had to work another part time job also, which I did for 2 years then, I got full time. So I quit the retail job. I started at the hospital in January and bought my house in June.
I would definately reccommend saving as much as you can, do not get a credit card, that is my downfall. If you do only get one and have them put only a couple hundred dollar balance on it. USE IT SPARINGLY. And if you can at all possible buy a car first and PAY IT OFF before you move out, that would save you another payment. I didn't have a car payment the first 2 1/2 years of living on my own. Makes a big difference