"Nope. No Way."

Cassidy's favorite thing to say lately is "Nope. No way." 
She says this when I ask her to do something.  And she means what she says.

This aggravates the crap out of me. 

I try to simply ignore this, and usually I'll just get up and leave the room.

In response to my telling her that it makes me upset when she says this, she has come up with a new, equally irritating response.

"Yes way."  Said with a smirk, and then refusal to do what I've asked.

She also is doing a remarkably good impression of me attempting to discipline her.  When she goofs off and refuses to cooperate while getting ready in the morning, I simply get up and leave the room, closing the door behind me.  This almost always leads to an onslaught of tears and sobbing, followed by cries of "Mommy, I'm ready" as she tries to compose herself.  I return when she has settled down and ask her if she's ready.  She usually chokes out "yes" and nicely cooperates  for the rest of whatever task we were working on.

Well, recently she's been pretending that she's the mommy, teacher, or ________ (fill in the blank with any person who is supposed to have authority over her).  The other day, I was sitting in her room waiting for her to come back in to cooperate while getting dressed.  She repeatedly came to the door, where she had closed the baby gate, and said "Are you ready to cooperate? No, you're not ready? Okay." and then turned around and walked away.  All of this was performed with inflections and body language in perfect imitation of me. 

Hmmph.

Yesterday she told me she told her teacher "NO!" when asked to clean up the baby dolls at school.

How can she be starting her teen years when she's not even 3 years old?!?!