If you haven't actually got to the romance phase of her affection, you can just hold off on talking to her and still continue to build affection. That way you don't have to worry about missing or turning down flirt options.
And Watcher 2 is speciesist, confirmed by the IA's writer "Well... she is pretty racist. (Species-ist?) It's her upbringing! I was pleased with how her romance turned out, though."
Hahaha. I had no idea until I saw a video of a human romancing her and I was like....WHAT....why is she being all warm and friendly and not trying to tell me we're "not compatible".