I would look at her with horror, then I would immediately kill her with a quick gunshot to the temple.
Since I have no children, her appearance would signify a huge rift in the space-time contiuum, and she would need to be killed quickly so that the normal time-flow could be restored.
According to modern physicists, the very act you perform in shooting her, thus embracing the sudden branch inherent in her appearance in your daughterless continuum, causes a separate spacetime continuum to flow from that moment onward ... while the stream from which the branch occurred continues on without being altered by the branching ... you started it, Laz. This is the stuff of them ‘virtual particles’ and ‘virtual continua’.