You love her, however, she needs to listen to you. Then, direct her to the request in a gentle and respectful manner, letting her know that she deserves respect just as you deserve respect. My reaction to my daughter would be to just walk away. I believe all preteens go through this struggle with control, not matter how supportive their family life is. They say something like that to get a reaction.
Compliance begins to happen.
If my son was continually saying this to me, initially I would investigate why he was doing so by simply asking. However, if my son did not have a reason, and just kept repeating this phrase, I would reach either one of two conclusions. The first, that he seemed to be hankering after some kind of disciplinary bounderies for his own security. The second, that I must have been using unrealistic threats which I could not carry out and I would adjust my behaviour accordingly. Then I would sit down with her and talk about the needs of the family, so that she see the reasons for the behaviors and or chores.