I think people are a bit confused. She never said that she wanted to quit; She said that she didn't want to cut her hair anymore, and then Jay said that she just leave the set. I'm pretty sure if changed her mind he would've told her to go home anyways. Other than that, all that they showed was her packing her bags and her leaving. So we may never know what happened.
YEa we don't know the full story but from what I've seen on the show I can honestly say that she coulda done really well. I don't like how she handled the hair thing (I wouldn't wanna cut mine eitehr but she already had it done so short...) but we really might not ever know the full story...she does appear to be a bit of a quitter...
It seemed like she left, not because she had to have her hair cut, but because they wanted to change who she was and change the person that she was, and Bre said she still respected her for leaving. Shame...