If I were 16 now I'd spend the extra time on Open Courseware and go to college only when I had done enough exploring on my own to really take advantage of the profs' expertise.

...and you would have ended up at community college. HS guidance counselors and college admission officers get this type of smartass thinking all the time and the answer never changes. Anyone can take the GED, it proves you aren't a complete waste of space. Anyone with half a brain can also graduate. What separates you from all the other mouth breathers is what you did with those 4 years. I, technically, finished highschool in 2 years. I spent the following 2 taking college prep and AP courses.

And that is how you go to college.

I completed the second year of high school German by spending a few summer days at the local library. The teacher lent me a second year book for the summer. I'd started my language requirement late, in my junior year, and wanted to make up time and get to a more interesting class. I'm pretty sure it was not much more than 10 partial days' effort, and maybe less. This was without a German speaker to practice with, other than a pen pal. (Well, Dad still remembered some from his school days and travels, but he didn't use it much and I did this on my own.)

However, I had just gone on a school trip to Germany early that summer. Just nine days -- not long enough to really pick much up German -- especially amidst a herd of English speaking contemporaries. But it was a great trip and so very motivating. (I've remained friends with the tour guide to this day.)