I would definitely check into community college, it sounds like you are unhappy with the direction your life is headed right now.
The community college's are a lot less focused on your high school grades and test scores though there may be an entrance exam, my mother has a GED and is a student now.
Personally in high school I had an awful GPA (1.38 I believe) and decided to do online college which works well for me though made me less eligible for aid. However I do well in school 3.91 GPA currently which proves it is never to late to make a positive change in your life. I waited over 10 years after graduating but should have done it much sooner.