The first thing Shepard clearly regarded was the suit. She hadn't expected someone to answer the door of their home in a suit, why would they? Was he working? It hadn't seemed like it from their PDA exchange. Was he one of those people who was always working? That would have made more sense, at least then he wasn't the kind of guy who liked to just sit around the house in a suit and tie. That would have been a bad first sign so, Shepard simply opted to assume it wasn't the case. Hoo-fucking-ray for optimism, a statement likely more valid than ever, considering their current state in life.
"Agent Coulson." She greeted him in a respectful manner, shifting her weight to drop the small bag by the door before outstretching her right hand, the good one, to offer him a shake. "Glad to meet you." She remarked, waiting for his response to the gesture, while taking a rather nonchalant look around the room, her eyes never straying too far from his face. It wasn't exactly any kind of secret, that she was trying to get a read on him.
Those kinds of things had become all the more important since her time hunting Saren and the Collectors, never mind working with Cerberus and trying to stop the Reapears. Even with her background and exploits, she was often seen as either a liability, or absolutely insane - and it only got worse if Batarians were involved, but she couldn't really blame them for that.