This really depends on where in the world you are located. Posts of this kind always have a bunch of answers along the lines of the parent post. The thing is, that is largely an American phenomenon, as far as I can tell. At least in Denmark, where I am from, this type of "life-changing experience" usually happens in high school (granted, we're in high school from 16-17-ish till 19-20-ish,) with college being less influential with regards to your social life/experience.

For what it's worth, I dropped out in my final year of high school, to freelance, start my own company, and eventually landing a job at a nice startup. So, while I don't regret not finishing and going to college for a single second, I wouldn't trade the 2,5 years in high school for anything in the world. That was the best time ever. So far, anyways.