I actually wrote out some thoughts on this and then my computer screwed up... I'll try again....
I think what you have to think about is if Nora is actually as silly as she seems. After all, she does have the cunning to take out the bank loan behind Torvald's back, and she does understand that she needs to play the helpless role in order to make Torvald feel as if he is dominant...
After studying the play, I started to feel that perhaps Torvald was the one who was really immaute and silly. He couldn't see past the facade that Nora put on for him, and was adament about complying fully to society's expectations. Nora however had subverted societal conventions when she took out the bank loan secretely... which was essentually quite a revolutionary thing for a woman to do to start with. So she was somewhat "revolutionary" from the outset of the play.
I also don't think Nora was as ignorant as she seemed either. I remember one part of the play when she was telling Kristine about the loan... she said something along the lines of that maybe she would tell Torvald one day when she was aging and was not as pretty. This to me illustrated Nora's understanding that her relationship with Torvald was based on factors such as her prettiness ("doll wife"), and this understanding was shown in an earlier part of the play.
So I think you really need to decide if Nora is immature and ignorant at the start of the play, or if she is smarter than she seems.