He couldn't be seeing that correctly, could he? Crowley distinctly thought her eyes looked a touch... red. That was more than unusual if it were really the case. People didn't just go around with red eyes. He supposed there was probably a way for people to change their eye color through the use of contacts, but that seemed unlikely. Just like the ears.
No, he was seeing things. “Hrm,” he said and just to be sure, lowered his sunglasses just enough to look over the rim. It was possible it was just the way the light went through this glasses. If the girl were paying attention she'd see yellow eyes, with thin reptilian slits. But her, her eyes were definitely red. Which was definitely not a human trait. Humans had all sorts of colors of eyes, but red was not numbered among the varities.
Which could have meant demon of some sort. She was no demon he knew, but Crowley was smart enough to know that he didn't know every demon Downstairs and that there were apparently people from different worlds here. After all, that demon hunter thought he knew Crowley, which turned out to be a different Crowley. It was all rather confusing.
Back to the girl.
There were two ways he could inquire of her demonic standing. One was to simply ask if she was an Advocate or something similar. But that wasn't very discreet. Instead he went with his usual greeting when meeting others of demonic nature and simply said, with a bit of reluctance to his voice, “All hail Satan.” It was up to herself to reveal herself is she so chose.