Why did Mrs. Daugherty become excited after she noticed Dough carrying a copy of Jane Eyre?

It isn't Mrs. Daugherty who's excited at seeing a copy of Jane Eyre in Doug's back pocket; it's actually Mrs. Windermere. Different adults seem to have different reactions to seeing Doug carrying this book around. Mr. Loeffler commiserates with Doug; he had to read the book when he was in high school and he hated it. Fortunately for him, he got appendicitis in the middle of reading the book, so had to stay off school for three weeks. When Mrs. Daugherty sees the book, she simply asks Doug whether he likes reading. "It's complicated," comes the reply.
For her part, Mrs. Windermere is most impressed with Doug's reading matter. He comes round to her house delivering ice cream; it's then that she notices the book in his back pocket. She invites Doug into her book-lined study where she shows him a first edition of Jane Eyre. Mrs. Windermere is very enthusiastic about the book, describing it as one of the world's great stories.