He didn't believe that he was simply being modest with his abilities, what would cause him to become an 'old man' before reaching an acceptable level to graduate to chakra...but he wasn't humble enough to make that argument, either. Certainly not if he'd managed to win her respect enough to have her use his proper name.

...It would be something of a shame if her belief that he used chakra was the one and only thing to determine that, however.

Rather than display either thought however, he simply canted his head to the side and offered her a faintly amused smile. "Finding teachers is a difficult order, you know. Unless...you're offering to be my tutor on the subject of chakra?"

He was, of course, teasing. To fluster her.