The way to a kid's heart maybe less through music at first, but more through stories. Here's a list of some of my favorite books about opera, suitable for kids. This is by no means exhaustive, just a sampling. Feel free to send in your own favorite titles:
Sing Me a Story, the Metropolitan Opera Book of Opera Stories for Children by Jane Rosenberg
Suitable for grades 3-6; and beautifully illustrated. Breaks down the intricacies (impossibilities!) of some opera plots.
100 Great Operas and Their Stories by Henry W. Simon
This book is good for junior high age. No illustrations. Very clear explanations of opera plots along with some historical context. A straightforward writing style, can be refreshing in this genre. This has been in print for years. It's that good!
The Random House Book of Opera Stories, by Adele Gerard is best for grade school kids. Beautiful illustrations. Pithy re- tellings of favorites geared to kids, including Prokofiev's delightful
Love for Three Oranges Aida as told by Leontyne Price Illustrations by Leo and Diane Dillon
The great soprano hosts a gorgeous book telling the story of her greatest role, Giuseppe Verdi's Aida, an Ethiopian slave held captive at the court of the Pharaoh of Egypt.
(It's my all time favorite!)
Stories of favorite Operas by Clyde Robert Bulla
High school age can read this without embarrassment. I enjoy reading this aloud to little kids. There's an added level of sophistication to the story telling. Clyde Robert Bulla (1914-2007) was a celebrated children's author. This book, originally published in two volumes, is worth seeking out.