Can confirm: My parents made me go through the grades one at a time, despite the principal's recommendation that I start in 1st grade, move to 2nd mid-semester, do 3rd grade in the spring, and do two a year after that. It was intensely boring. I can see why they thought a bunch of teens and young adults wouldn't want to be friends with a much younger child, but I've always wondered if they would have been more willing to overlook the age difference than the other young children were willing to overlook the fact that the only thing we had in common was our age.

Ironically, I found it decent preparation for life, though, which seems to be occasional bursts of furious activity punctuated by long stretches of repetition, which could easily become boring. I ended up becoming very good at taking responsibility for making my own life interesting.