I wouldn't assume anything. It's very possible you read too much into her smile because of your attraction to her. But hey, you never know. If you want to go back and try to talk to her, I don't think you've got anything to lose.
“This planet has - or rather had - a problem, which was this: most of the people living on it were unhappy for pretty much of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movement of small green pieces of paper, which was odd because on the whole it wasn't the small green pieces of paper that were unhappy.” ― Douglas Adams, The Hitchhiker's Guide to the Galaxy