It is a sign of getting stuck in 'good old times' ;-)

You told us of a joyful moment ('piti') and a minute later a disaster struck (in you mind)

I would let live and let go -- because it is 'anatta' (not ours).

An alternative could be:

I would rather smile and call that girl away from making a spectacle of herself -- but without making a scene for myself. I would compliment the girl and would suggest 'kusala' deeds and 'paramii' may come to those who is aware of what they do. There I must stop ;-) -- once again 'it is anatta'.