I always fiddled with a toy one when I was ten, and Then my grampa gave me my his old one.
If you want to learn I'm sure a book would help. I never used one, I had my grampa teach my the very basic stuff and I played piano at the time so that helped.
In the end I think the best stuff I ever learned came from the paul butterfield blues band. Really, just listen to stuff like that and try to learn it by ear, but that's just my opinion. (The harmonica playing on screamin' is amazing, and the guitar playing is pretty kickass too. :D )
good luck with it!
War?