Zuko was also pretty surprised at the abrupt question.

He stared down at her, silent for a few moments, and then tore his gaze away to the side. "There was a war meeting with the generals years ago," he began to explain, his voice going quiet. "I was too young to attend, but I insisted that my uncle let me with the idea that if I'm to rule the Fire Nation one day, I should prepare early, and he did. Under the condition that I keep quiet."