Sounds normal ... for around here!
Try and keep up with his interests, give him lots of books, and see where he's leading you.
Look into schools and learn everything you can about gifted education in your area now, so you'll be ready when the time comes.
Most important, don't let people give him a big head about how smart he is and how amazing it is that he can do all that stuff. Try and instill an attitude of how good it feels to work hard on something, rather than to be able to do something. Perfectionism rears its ugly head early, and it sounds like you have the makings of it there already -- and when one is accustomed to knowing everything, it's a hard fall to discover that there are things one doesn't automatically know. That leads straight to "why bother" and laziness and depression and lack of work ethic and lack of self-esteem.
If I had realized all of that with my son when he was the age of yours, we might have averted some problems -- and it should have been blindingly obvious to me, because it's exactly what happened to me as a child. But it's hard to show the fish the water.
Someone will undoubtedly come by here with some good book recommendations for you, and some lovely advice. You're in the right place. Enjoy the ride!
