Seriously? That was going to be his argument? She was starting to think she was correct in her estimation of his age. He certainly sounded quite young. "It's not a matter of being the boss of the park. It's a matter of using good sense, which you aren't." If he wasn't going to take a subtle hint then she'd go with the hammer routine instead.
"You're only trying to transfigure things into small animals. You could get it wrong. And then you could hurt someone. And when that happens? Then you're in trouble. And your guardian." She still didn't believe he was who he claimed to be. Maybe he'd hit himself with a spell? He was still talking quite oddly.
"Mhmm, yours. Right." She sounded completely skeptical. There really wasn't much of a way he was going to be able to convince her that he was Nikolai. He looked and acted too different. He seemed too young.