Part of the short catechism of librarians. The original is "his", not "her".

I'm sure with another book, of equal length, and even with the same relative amount of narration, she would have been enthralled. It depends on the topic, and on whether she could identify with the characters, or with at least one. The Hobbit is a ripping yarn set in a boys' club. I wonder what she would have made of Little Women.

I read The Adventures of Tom Sawyer to my son when he was 6, and his 4-year-old sister wandered across the hall demanding to be included. They both loved it. I had to read until I was hoarse every day. Now, mind you, I skipped bits that were too heavy or long-winded, which as a narrator, you are allowed to do. (In Twain's case, this was the social criticism department, the graduation speeches, principally.) Reading is a contract between the author and the reader. As readers, and as interpretive readers, we are allowed to bring our needs to the book, and even to leave things out as long as we say, "I'd like to skip this bit because it gets too long and doesn't do much for the story. Do you want me to read it anyway?" It's not censorship if the listener knows that there are things missing and has the choice to hear them.