In my country we have specialised highschools which take 4 years to complete. My field was IT. Got trough with D's and at the end I didn't know almost anything. Final exams summarizing everything came and I crammed everything in in 3 months of propably 6 hours 5 days a week study. Picked up the worts questions I could imagine (almost passed from the shock). A's and B's was what I ended up with on my final exam.

The truth is that I am not super quick learning genius when I want to be. It is just that average person could learn that in three months of serious study. The school program just scheduled it for 4 years because of the efficiency of how high schools in my country work.