She certainly is.  I had mixed feelings about this chapter, since it pretty much set the story to a certain tone... but much like Valerie, if I could do it all over, I'd have Crystal's story end the same way again and again.  But these first 7 chapters were always my favorite because of the dynamic these characters had, and what Valerie ended up doing with Crystal leaves some permanent repercussions to Valerie's other relationships.  I feel like the story became darker as a result, but I guess that's expected given that Valerie is like sprinting down said dark path.