To echo others on this thread -- whose definition of "success" are you using? Success can be deceiving, anyway. I know quite a few people who make six figures but hate their jobs--would you consider them "successful"? There are a lot of things that society says you should want -- marriage, house, kids, higher salary, etc -- but not everyone actually wants them. If you don't, that doesn't mean there's anything wrong with you.

Like you said, you've always worked, which is significant. And you're going back to college, which means you have motivation to change whatever it is you don't like about your life. That's something you should be proud of.