"No, Mamma" and Time Out

Nora has become quite the independent little lady lately. She wants to do EVERYTHING on her own and if I try to help her she will quickly respond "No, Mamma". Needless to say although she is quite capable of doing many things on her own, she is ONLY 21 months old and therefore some things just need a little of Mamma's help. For instance, Nora likes to push her highchair to its "storage spot" after she is finished eating. I am fine with this, however, since her steering skills are not up to par, I like to help guide the chair in the right direction. She does not like this and so the "No, Mamma" is quickly put to use. Last night she was overly full of "No, Mamma's" and I had had it so I told her, "Nora, if you tell Mamma no one more time you are going to time out". Her response?  She immediately stopped pushing the highchair, turned around, stated she was going to time-out and sat herself down in time out. Apparently time-out is a fun place to be at our house. Now to find an effective form of discipline at our house has been added to my to-do list. Silly little girl, when is the orneriness going to stop?