Oh he hadn't messed up at all. But he also definitely didn't have the words or emotional intelligence to properly react to what she had said either. He felt very warm in his chest and pleased with himself for making her so happy, but he had no idea how to express that.
"Oh," he said, nodding awkwardly. "Well, you're welcome," he said, still nodding. "This man, Charles, he wrote a book about a girl in a mirror. He is still looking for more. I couldn't remember everything to describe it but now you can."