You're the only one who can ultimately know what will help you learn. In general, I think it's a great idea to keep track of what you've learned (e.g. taking notes) and what you'd like to learn (e.g. your spreadsheet); so as far as that goes, good on you!

FWIW, I keep a mind map (using FreeMind, since it's free, but there are other solutions as well, including pen and paper!). I put "Perl" in the center, and when I learn a concept, I add a branch and put a check mark by it. The very act of doing this usually prompts me to think of two or three related things I'd like to learn, and they become sub-branches.

As soon as I learn one of them, I check it off, and again it expands. It's been so useful to me that I had to split it into about 10 maps broken up by topic, just to be able to keep track of it all. (Of course, then my employer pushed me into a role where I do Java almost exclusively, and my Perl has stagnated a bit).

I'd be curious for any of the elder Monks to share their methods (if any) to keep track of what to learn next...