I have self-taught myself everything I've learned in software engineering, beginning in middle school when I picked up a VB6 book. Then through high school/college with some C++, Delphi, and then eventually moving to the LAMP stack and beyond. Although even before getting into college I knew exactly what I wanted to do (I was bitten by the entrepreneurial bug early in my high school years) and knew college wasn't going to do much in helping me achieve my dreams, I was still excited for those 4 years.
I wanted to have that college experience rather than looking back years later in life and saying "man I wish I got to see what that was like." But more importantly than the experience of college, I wanted to learn things I knew I'd seldom get the chance to later on in life, such as philosophy, art, history, astronomy, finance, theology, etc. While many argue that you can learn those things on your own without having to go to college, and yes I agree anyone can order an eBook or go to your locally library and pick up a bunch of books on those various topics, but it won't be the same as getting taught by a professor who has spent a great part of their life learning, teaching, researching and working in those various fields.
My goals in life have been not only to be a successful entrepreneur and a great engineer, but to also be a knowledgable man overall, one who is well versed in a number of topics. And while college won't give you all of that in 4 years, it'll definitely help you get started on your journey.