Sorry for dragging up an old(er) thread, but thought I'd add my $.02.
My parents bought me a Sno Scoot for Christmas when I was 7, turning 8 (birthday in January). I had NO problems riding that machine, and I was just an "average" scrawny little ~8-year-old!

I had the Sno Scoot 'til I was 13, at which point I had really out-grown it (not to say I physically couldn't ride it, it just became too slow for my riding capabilities).
If I could ever find another one for a decent price, I'd probably get it just for sh!ts and giggles!

I also had a friend who was 1 year younger than me who got one at the exact same time I did.
Huh, huh, it was riding the Sno Scoot that I learned to "drift"!!!