My DS had his first one get wobbly right at 5.5. His have been funny, though - the new teeth are popping up BEHIND the baby teeth. Freaked me out at first, though I read somewhere that it's a variation on normal. I call them his shark teeth.
So the first tooth came in before the loose one got knocked out - which was so anti-climactic that no one noticed and it's truly "lost!"
(I was out of town!) The second tooth has broken through now but the baby tooth isn't loose yet...
He'll be 6 in March, and his friends of similar ages are all starting to lose theirs, too. Though I'm seeing the same pattern of how early/late they came in originally corresponding to how early/late they're being lost.