Attitude

So we are dealing with a little smart mouth right now. Kennedy is only 3 and acts like she is 16 already. Its crazy! She got in trouble the other day by her daddy. He told her that he was tired of her smart mouth and that she needed to watch how she talked to us. She said "yes sir" like a good little girl, then 2 seconds later as she is eating her dinner she says "but i can say what i want to". That made her dad so mad. Every day she is getting in trouble for something she says. Yesterday she told her pepaw that she didnt want to listen to him and didnt have to mind him. Not sure what we are going to do with her! I have no idea how we are going to deal with her when she is a teenager!