Susan wasn't opposed to flirting, it's just something she wasn't used to. She wasn't known as a flirt, in Hogwarts she was known as the maternal Hufflepuff who cared more about other people than she did about herself. She was notorious for dropping all her stuff and rushing to those in need. It was both a positive trait and a negative one.
Susan shrugged slightly, she wasn't about to argue with him. Susan knew there were plenty of jobs out there that could utilize his skills with plants, but if he had his heart set on quidditch, who was she to convince him otherwise? After all, Susan is a successful businesswoman from working with plants. Of course, an apothecary isn't just all about plants. It was mostly potions, actually, but considering most potions came from plants, Susan made it her goal to incorporate plants into her shop.
Getting lost in her own thoughts, she seemed to snap out of it when Marcus asked if he was going to be allowed to ask her questions. Cheeks flushed a slight pink once more, as she nodded.
"Me? Of course, I'm sorry, I guess I got carried away." Smiling, she ran her fingers over the napkin in her lap, and sat up a little straighter as if she was preparing herself for something. "Likewise, you may ask me anything."