I have given my 4yo daughter a nightie for the first time. She is delighted that she is so grown up.
However, she is not particularly 'lady like' in her sitting and rolling around in the living room after bath time. I've therefore told her to wear pants under her nightie.
I'm uncertain whether to tell her to take them off before bed.
What would you do?
A bit of free air time vs. risk of a flash at bedtime and free access to for her to fiddle. 
Advice please?