Happened to me several years ago.... then a while back... and then last year.... then more recently.
Smile and talk.
What could possibly go wrong?
If I were you I would take a chance ask her out for a coffee maybe you never know she might fancy you a be waiting for you to make the first move if you don't ask you don't get what's the worst thing that can happen she says no big deal life is too short for what ifs our maybe I should have.