Where does it come from?

When I'm not maddened by Shelby's sassy personality, I am usually amazed at the things she comes up with. I just spent tons of time with her this summer and she says things that make me ask myself where she learned it. One day last week we were in the car and a fly had joined us. Shelby does not like flies , so I hear her in the back saying "Go away, fly, go away!" Imagine this loudly through clenched teeth and repeated over and over and you'll have a good idea. She does this over and over for a couple of minutes (the fly was not going away) while I'm laughing to myself in the front seat (she sounded so cute and funny). So then I told her to tell the fly to shoo.

She says "Shoo fly, don't bother me!" Where did she learn that phrase? I have no idea, but the fly listened because it listened and came up by me so we could shoo it out the window.

Just had to share the story, I wish I could have recorded her!