"I think it means you can choose to be one." She doesn't necessarily believe everyone gets to choose. Whatever she is now, there was no thought involved, no planning and no real choices. The few things she has decided to do only made things worse--and that's why she lives moment to moment, doing what her impulses ask her to do, never slowing down to examine them.

Like for instance this impulse, when her mouth brushes his. "What do you choose to be right now?"