The strange women lying in ponds as a method of government.

If we're assuming I'd change something, one of two: either graduation or the end of third grade.
Graduation: I'd apply my current mindset and skip eight months of sheer idiocy.
Third Grade: This might be better, although I'm not sure whether it would be better to eliminate the possibility before it started (unless it's genetic, in which case that SUCKS) or leave it and just attack the worst of it. Probably the latter - it wasn't that bad and I learned a lot.

HOWEVER, if this a "best day of your life" kind of thing, I'd come up with a list:
Any normal day in 8th grade, really. Before Isi left, preferably.
Dinner Party
Theatricum Bonatancium
Getty
Getty Villa
Thanksgiving
Valentine's Day. It wasn't the best, by far - no Catherine, no Cooper, no community - but it was the day I felt the best. Steel Hammer, Rubber Hammer - isn't it weird that I reverse the analogy so that LA is the rubber hammer? COREninjas, at least, know how to have a good time.
5th Grade Graduation - just to have the feeling of knowing I had complete bliss ahead of me
A CSUN Day, the last year. Probably one of Nana or Granddad's days. But not one with the phone thing, because that was so ridiculously, stupidly juvenile that it would be a total buzzkill. Crazy lady.
The day I came up with Flottementia, or as it was called then, Terre Des Flottements. I'd laugh. And laugh. And laugh and laugh and laugh, laugh, laugh, laugh, laugh. And then I'd laugh some more. I might be able to stop laughing before Ivy edged away and talked to my parents about psychiatric assistance. Or not.