Got lost here by way of Okusan and remembered how great this manga was, with the exception of the last volume tone shift.
Before that, though, it's probably one of the funniest manga I've ever read. For something that makes you cringe at all the first grader underwear shots -- she's actually a high school boy I swear officer -- it's incredibly funny and surprisingly heartwarming, with a remarkable grasp on how actual children behave and view the world. The MC especially is charismatic, hilarious, and thoroughly likeable. It's legit...aside from the underwear shots, that is.