A qualifier: If you're going to do this, make sure it's a class where the other people in the class actually want to be there. Otherwise the social reinforcement will be misdirected. This is an obvious failure mode of grade school and a less-obvious failure mode for the sort of extracurriculars where the students are there mostly by parental insistence.
(also, make sure you actually want to be there too. Otherwise you'll be the one screwing it up.)
LW has a problem. Openly or covertly, many posts here promote the idea that a rational person ought to be able to self-improve on their own. Some of it comes from Eliezer's refusal to attend college (and Luke dropping out of his bachelors, etc). Some of it comes from our concept of rationality, that all agents can be approximated as perfect utility maximizers with a bunch of nonessential bugs. Some of it is due to our psychological makeup and introversion. Some of it comes from trying to tackle hard problems that aren't well understood anywhere else. And some of it is just the plain old meme of heroism and forging your own way.