She wore rocawear because she wanted to, not because she needed to, but because she wanted to prove a point. A point in which she had to prove because if she didn't, she would be taken just like all of the rest. She had to fit in and there was no doubt in her mind that this was the only way to do it.
To play their game or else they would know something was up. They would know she was not one of them and she had to be or they would kill her. Yes, in reality, she needed them in order to survive.