Huh, that's interesting that you just remember that one thing and then nothing for a long time. I too remember very few individual events, but I do remember fairly clearly starting piano lessons (at age 4) and what I was for Halloween almost every year:
Preschool - a knight
Kindergarten - the two of clubs
1st grade - a red crayon
2nd grade - don't remember
3rd grade - a vampire
4th grade - Harry Potter
5th grade - Tae-Kwon-Do person (admittedly, this was kind of a cop-out, as I was actually in Tae-Kwon-Do).
6th grade - Sherlock Holmes
7th grade - This was the last year I dressed up for Halloween, and it was also the first Halloween that I had a dog. So I had this GENIUS idea that my costume would be to "switch places" with my dog, by putting him in jeans and sunglasses, and putting a leash on myself and having him hold it, and I would be constantly holding him up on his hind legs, and attempting to say "trick-or-treat" ventriloquistically through him. Unfortunately, my mom didn't appreciate the GENIUS of this idea, calling it "impractical" (psh) and so I just threw together this shitty costume at the last minute consisting of a black garbage bag with eye, nose, and mouth holes cut in it, and a broom, claiming I was the "dust bunny Grim Reaper".
Also, there was some birthday (don't remember if it was 4th, 5th, or 6th) where I had this incredibly badass birthday cake that was shaped like a caterpillar. A bunch of pieces of black licorice were used as legs.