Coming-of-Age
Taylor is technically an adult already by the time she breaks away from Pittman County, Kentucky, but her view of the world has been so limited by poverty and a rural upbringing that her transition into a more experienced, more knowledgeable adulthood begins for real once she finally gets out of town.
Needless to say, Taylor's shift into a whole new kind of adulthood is also helped along by the fact that she suddenly finds herself responsible for a life other than her own. Although her new role as an adoptive parent isn't the only thing that forces Taylor to "come of age," it certainly makes an impact.