I'm 23, live with mom, and decided to go back to school. I know, people will say "But you live with mom," I've been helping her pay the mortgage since I was about 15 years old. I didn't think school was for me five years ago, barely went (high school), almost dropped out, but graduated. Spent three years working shitty jobs and realized I can't get anywhere like this. I now work two jobs, and go to school full time. I Work six days a week and my day normally starts at 4AM to go to work at 5-530, then class, then my second job, then I get home to do homework at about 9-10PM to start all over again the next day. I am one semester away from getting my AS in Marine Engineering, to transfer it all to Mechanical Engineer for my bachelors. I have a 4.0 (so far) and I somehow manage to get through life without sleep. I know I'm young, lack "life lessons and experience" according to my elders, but If you really see yourself benefiting from your education, and see it as a worthwhile investment, go. Don't go "just to go," you will not be happy half way through, and drop out. Go because you can honestly see yourself in a better situation in a few years than you are today. And do your best, don't half-ass it, put 100% into it. Ironically, I find myself saying this to quite a few people I know who are working their asses off just to get by. Unfortunately, they don't think school is for them, even though they are younger than me, and have the best opportunity to go to school, before life (aka: spouse, housing, kids, and bills) take priority.
If you think going through all four years of a degree is too long to put yourself through, vocational/tech/trade schools can also help you get to where you want to be with half the time investment.
Also, state, and community colleges are far cheaper than private institutions. And "For Profit" schools cost about 3-5 times as much as a state funded school.
You may also qualify for financial aid if you apply. If you get a grant, as long as you get good grades, those classes (or the grant paid portion) are technically free for you. (unfortunately, I can't get aid =[ )
The first thing you have to do is commit to yourself to go through 2-5 years of textbooks, homework, essays, and testing, and search for the best college for you. Then, apply.
Sorry for the long read, but whenever someone is contemplating going to back to school, I can't help but to want to give them the information the no one ever gave me. Trust me, I can go on for hours about this. Goodluck!