Whilst we're quoting Good Will Hunting this seems apt:
"Sooner or later you're gonna realize you dropped 150 grand on a f***in' education you could have got for a dollar fifty in late charges at the public library!"
But srsly, if you want to expand your mind and find out new things you don't have to go to school, the structure of lectures and essay deadlines would likely bore you and having little motivation to complete would make it very difficult.
There is a never ending wealth of information you can full your mind with and unless getting the accreditation of the degree itself is important, you don't need school to get it.
Start here:
www.academicearth.org and watch the best lecturers in the world from Harvard, Yale, MIT etc talk about morality, quantum mechanics, game theory or whatever looks interesting to you and become enlightened.
If you become enthralled with a particular aspect to the extent that you're looking at the midterms and sitting them yourself then maybe find a good school and do it (I dare say your story may mean you can go to America and do Harvard etc providing you show a high level of enthusiasm but I'm not 100% on that).