Perhaps one of Tolkien's genius touches was to tell the Ring stories through the eyes of little people, the Hobbits. The ones always being patronized by all the bigger races, while being protected by the bigger people. The little people always being underestimated, and the ones who, in the end, save the world.

And Frodo grows up, some, not dramatically, it's not a coming-of-age story. But he grows outside of himself, becomes bigger, through the journey.

And, and again, the smaller viewpoint I think makes the story accessible to everyone regardless of age. You don't have to look like a hero, or even think of yourself as a hero; and you don't have to be a born fighter and big and strong. You can be small, and still be the center of the universe.