I met a girl a couple months ago at a party, she's a student in the same program and faculty as me, just a year behind me. I added her on facebook but never contacted her. Earlier this week she sent me a message because she wanted to buy textbooks from me. We met, and after chatting for a bit i asked her if she'd like to grab dinner, but she said that she just ate so i left it at that. i told her that i'd be studying this weekend at a cafe, and that she was welcome to join me. We met yesterday for a few hours but didn't get any work done, we pretty much talked the entire time. The whole thing ended up being ~2.5 hours and we got along really well I think. But while we were talking about relationships she mentioned that she enjoys being single. I originally thought that she might possibly be interested in a relationship because she was open to meeting up to study (I barely knew her at that point). Later I asked her if she'd like to grab dinner, but she said no because she had to go to a friends place.
Am I right in thinking that she's not interested?