I'm going to give you some unusual advice, considering this is a distance education site. I recommend taking a year, or even more, to explore what it is you really want to do with your life. How many people really know what they want to do for the rest of their life when they are 17 or 18 years old? Not many. There are many people who work in two or more different career fields over their lifetime because even after going to college they weren't sure what they wanted to do. You have the rest of your life to work a job or go to school. Plus, I believe that older adult students who do go to college are more motivated to succeed in their studies. Some younger students use college as a place to socialize, party, etc. Face it, you don't have to pay $20,000 a year or more to go to college and do those things.
Take a year or two and explore different career fields, travel, do volunteer work, join the Peace Corps or similar organization or maybe even join the military for a a few years (which will pay for your college education if you do decide to go to college). If you were not a good student in high school, you will not be a good student in college. You may even discover a career you really enjoy which doesn't require you to get a college degree. To a certain extent, college degrees are bit overrated, especially if you decide you are going to work in a trade occupation such as plumbing, HVAC, welding, construction, computer repair, cooking...none of which require a college degree. You may discover your educational needs can be met through an apprenticeship or a vocational school.
If you decide college is in your future, you could certainly take care of your general education requirements through CLEP and DANTES exams. There are also schools which offer inexpensive online courses, such as Louisiana State University, or Clovis Community College.
Remember, there is no need to rush into a college degree program. Other than buying a home, it is probably the biggest investment you will ever make.