I'm not going to allow a little old lady to in line
Why don't you allow her to get in line?
I don't feel it is ok for anyone to skip ahead while waiting in line.
Maybe that person has an emergency and needs to get out quickly. If not, tell her to go back at the end of the line.
I feel she should respect the rules and wait like everyone else.
Upholding social norms can be a good thing but if would not hurt to see if there was a pressing reason before deciding for sure.