Most Helpful Girl
I know I am essentially saying what the girl before me did, but here is a second opinion for conformation.
When you don't make some type of move pretty early on or at least recipricate my flirtiness I try to move on or not push that avenue. Guys are known to be visual creatures and if you're not showing that interest early on I don't feel like that's going to change. When she said not yet she probably expected you to then ask her questions or make an effort to get to know her, if you didn't that would feel a like a minor start of rejection. I know it may not always make sense, but being as sensitive as I am I would feel a sting of rejection and try to back away