I agree with Kaliope...it sounds like you are over-reacting.

Put several people (or dogs or cats or chickens) in a room together, and they will quite naturally work out a "pecking order". That's what's going on here.

Maybe she thinks you are a little slow or disorganized, and she is trying to exert some control, to get things moving along. Your best response is simply to say, in a friendly manner, "Thank you, I've got this" or whatever, the next time she tries to exert control.