Welcome to a life-long addiction. The important thing to remember is that results/bagging something is only one part of it. Being out there with your son walking around is something he'll always remember, and most likely will pass on to his kids when he's older if you two stick with it now. You will be surprised how much better of a hunter you'll be as time goes on, and not even that far into the future, I'm talking within the next year or two, its a steep learning curve at first and then a lifelong slow curve after that.
As for turkey hunting, I think thats a great way to go. Theres nothing more fun for a kid to do (grown man as well) then dress up in all camo and facemask or face paint, running around the woods chasing turkeys, and calling back and forth with them. Any of my friends who show interest in deer hunting, I take them turkey hunting first because its so active and fun, then later comes things like grouse hunting/rabbit hunting where you can put in a lot of miles with little success even if you're doing things right, and deer hunting where you can freeze your butt off waiting for a deer to come by. Have fun and good luck, and never, ever forget the snacks!