First world kids who have the luxury of setting high expectations for themselves tend to beat themselves up most when they are in the midst of discovering whether or not they can actually meet those expectations.

I would like to say that this explanation you've put together manages to sum up the most recent period of my life perfectly. (I'm 27 and 9 months, even the age range fits well.)

Considering the cognitive load I was under earlier this morning trying to resolve problems related to exactly this, The feeling that I'm left with is the one Eliezer mentioned in http://lesswrong.com/lw/of/dissolving_the_question/ where all of the unexplained bits and pieces that I was going crazy over are just gone.

I even thought "But wait, what if there is something I missed that would make this a bad explanation that I'm letting myself get fast talked into." (mental review) "Can't find a thing, it really does fit every bit of evidence I can think of."

Thanks!