Ahh curiosity. Humans had a saying about that and cats, didn't they? She asks a question that is a bit too dangerous to really give her a full answer. But she likes the game, she wishes to continue playing so she needs to give Elsa a true answer, something satisfying. "Winter." She replies, "My purview is winter, thus the ice and snow. I am the Lady of Air and Darkness." Which tells her everything though not to a dangerous extent. That aside it would take far too long to fully explain the extent of her magic. If Elsa wanted detail there would have to be a deal made. A question too all encompassing was difficult to really narrow down.

"You seemed somewhat at odds with your ability." Not terrified, but she'd definitely been struggling in the coffee shop even if it was just the fear she might not be able to control her emotions enough to keep the whole shop from noticing what she was. "Is that a regular occurrence?"