Orla didn't really have any expectations in regards to who the Ministry paired her with; she only wanted them to not be mean. That was it. As simple as that. Merlin seemed nice enough, though perhaps his outward appearance was different than she had imagined, but she hardly paid attention to such things usually. He was courteous enough to perform a charm that got rid of the cigarette smell and that made him already seem nicer than others.
"You're taller than I thought," she found herself saying and then blushed lightly at how ridiculous that might have sounded. "I mean - I don't remember you from Hogwarts, so I didn't know exactly what you looked like so I kind of imagined it?" This was definitely an embarrassing way to start off a conversation. She always had been wretched at doing that with people she wasn't closest to.
"I'm sorry, I'm absolute rubbish at this -- it's nice to meet you?" she added a few seconds later and held her handout to him, hoping that he would just forget her you're taller than I thought comment.