After college, it has been very difficult to continue learning math as a hobby, I have the time for it, but I get incredibly frustrated when I run into something that it feels like I will never ever understand.
As an undergraduate you are basically shielded from this kind of stuff. The reality that you are climbing a mountain which extends into space is replaced by the illusion of grades and homework and it makes it a lot easier to keep marching forward. I don't want to carry this anxiety into a graduate program.
Is there an online resource that is dedicated to the partial ordering of the topics of the undergrad/graduate curricula? Ideally, I want an exhaustive list of mathematical topics which are not, to mix metaphors, out of my depth.