This reminds me- I was on another board recently where a man introduced himself as the father of a 4th grade math prodigy. His son was doing algebra. Not that this isn't advanced, but there are probably more kids like this out there than that Dad realizes. 4-5 years advanced isn't so unusual from my point of view. I suppose it's all relative!

I think of prodigies as kids ten and under who perform at the level of an accomplished adult.