Go see it! It's been decades since we had such a great movie! It's in the same genera as Princess Bride, though quite different from it. The scenery is wonderful, dialogue and music, acting, the whole thing is a 10 all the way around. I will buy it as soon as it comes out in DVD.
I would not say it is a children's flick, and wouldn't recommend under 12, depending on the maturity of the 12-yr-old.
Just WAIT until you see Robert DiNero!