Making a Little League Dad an umpire is one of the best things you can do. If you enjoy the job and want to stick around, the league will have a willing umpire for years to come. (your kid is only eight, thats at least 4 more years of enjoying his games from behind the plate!!)
It sounds like you have the desire and will to be a good umpire. We all have to start somewhere. I'm fairly new myself at three years. My advice is to get as much training as you can. Attend all of your league clinics. And find someone you discuss things with. And don't bury your head too far in the rule book. Its one thing to know the rules, but another to know how to apply them. I'm still learning that one myself
Just use a lot of common sense, and have fun.
A quote I read somewhere about umpiring is that it is the only profession where your job is to piss half the people off all of the time. Don't worry about pleasing the fans.
You'll find plenty of enjoyment within the diamond.
Good luck.
Phil