It depends upon one's definition of young adult (YA) literature. To some, YA literature refers only to fiction that is published specifically for or marketed specifically to young adults, defined as ages 13-18. To others, YA literature refers to any literature that is chosen to be read by this age group. Still others believe that YA literature includes works that are of interest to this age group and works that contain characters that are in this age group.
With that all-inclusive a definition, almost any book could be considered YA.
This book was written by a young woman, but not in this age group. It does not appear that she wrote the novel specifically for this age group. That said, the main character, Amabelle, is in this age group when the novel begins and the themes and plot of the story could be of interest to this age group. Certainly the themes of exile, genocide, death and survival are are weighty issues and may not appeal to younger teens, but older, mature teens would find these issues compelling and, in my opinion, would want to read about them.
It has been my experience that teenagers are very interested in the human struggle and how characters overcome adversity. So while there are some parts of this novel that might scare some teachers in our public schools, I personally do not feel it is any worse than some of the others novels we teach and allow students to read. Like with anything else, it depends upon the maturity level of the reader.
By the strictest sense of the definition, i.e., that YA fiction is written and marketed specifically to young adults, I would have to say that this work is not an example of the genre, but would I teach it to teens? Yes.
Read about it here on enotes and see what you think.