|XP is just a number|
"...my knowledge was about a week out of date..."
I find out-of-datedness less of a problem, as it will give you a sense of history in the end. Which will hopefully make you realize that all those nice things in Open Source didn't get there by itself, but were the result of hard work of countless, and often nameless, contributors. As long as it is clear which knowledge can be applied where (as in: in which version), I don't see a problem.
It will also make you realize that there is no "definitive" truth in programming (as anywhere else in the world for that matter). And that you should always verify. "Trust, but verify". There are even <plug>conferences</plug> about this.
Personally, I find that the combination of my 25 years experience in programming, combined with my programmers' laziness, tends to trip me up when I start making assumptions. Assumptions based on my experience, of course, but not necessarily having any foundation in "current" reality anymore. In that manner, I find the openness of Perl Monks, and the willingness to correct (in my case, mistakenly perceived) authority, refreshing.
So I can only concur with BrowserUk: "The only way I am ever going to know if what I think I know is correct is if people who know better correct me when I am wrong.
So please, correct me. I welcome your input. I may not directly accept it at face value, but if I don't, I'm not saying that you are wrong, I'm only saying that I am not sure that you are right and I would like further input to allow me to reach that state of grace.".