TL;DR: Unfortunately, I'm left with (what I feel is) a bit of a dilemma. I still feel fairly behind in math. I have the standard k-12 math curriculum down fine, but there are many topics that seem interesting and important that I feel I should've touched on years ago. Am I right in thinking this? Topics like "these"[/URL], or the topics covered in Courant's book "What is Mathematics?" come to mind. Is it worth my while to learn such topics now, or is it kind of "too late" in that I should just wait to cover them in depth in college?