Just take it…
As said before, do not ask too much. Your job is not asking questions but taking pictures. So, even when she is moving, arranging herself or her dress or whatsoever, shoot ! If some of the taken pictures do not match your taste or hers you can eliminate them later on before processing them. So have fun and do what you can do: Shoot the moment and enjoy it.
Olympus E-M5, no flash only ambient light