I was one of those people who knew what they wanted to do when I graduated high school, so I was ready to go to college and loved the experience.
After I graduated, I felt burned out and didn't really feel like continuing with grad school right away, and chose to go into the work force. Unfortunately the jobs I was hoping to get all were cut due to several issues with the country at the time (I was just in a bad part of the cycle), or I needed a PhD to get them. I ended up working someplace that did use some of my skills that I learned which made me a little bit happy.
Then I ended up taking a job in a field that was more of a hobby than a career (computers), and about 10 years after I graduated from college, I went back to college to get a degree in my current career - mostly because at the time it was good to have a degree in computers because I didn't have the 10 years experience in the field if I needed to get a new job (our contract was up for renewal, so we were not sure how things would pan out).
I ended up getting my second degree by going to school online vs classroom. Now there are so many options - classroom, online, blended (half classroom/half online) - so anything's possible.
I also had a friend who went to college at the same time I did (the first time around). She ended up dropping out and moved to New York. A couple years ago she decided to go back to school there to finish her degree, and last Spring she got her diploma, and is now working on her Masters.
It's never too late to start, nor is it too late to go back and finish.