What is the author's style in The Upstairs Room by Johanna Reiss?

The point of view in the story is written in first person from the point of view of Annie. The point of view is past tense and while much of the story is told from the point of view of a little girl, Annie, there is a lot of historical facts that are included in the story and dates. The point of view in the story will almost seem to change because Annie is so young when Hitler begins to amass his armies. Annie is just a little girl at the beginning of the story that is certain that they are safe because they are so far from Hitler and the Jews that are being put into prisons.