For the record, this has happened to me before, and I didn't make a move. A year later she told me she used to have a thing for me, back then. A couple years later now, we aren't even really friends anymore. Better to give it a chance and find out than not. As simonj said, your friendship won't last forever anyways. And no, it doesn't still bother me, but I do occasionally wonder what would have been different.