I think this book should be reclassified as Christian Inspiration. The Christianity is a bit overpowering. It comes on too strong. Her family, so perfect and so Christian, Sophie brought up so right and then their Swiss/German side of the family, irresolute, having affairs and seem to have no scruples. It's an irritating part of the book. I feel like it should be classified as Christian fiction, since faith is one of the main themes.
Sophia is innocent, as is made clear by the title, but she's too sheltered, I think. She has no concept or idea about the war, (she puts off thinking about it, or says she's thought about it enough so she can worry about why a boy didn't show up for their date) yet she was raised as the daughter of a military man. Her reaction to her cousin's outburst after he learns that his family has been killed was to be shocked that he had said something irreligious. She doesn't seem to care that hundreds of Poles have been killed, only that her cousin was angry at god.
It seems to end where the story really ought to begin, but I doubt I'd read the next. Sophia wasn't a compelling enough of a character for me to follow. Again, I think this would market well towards Christian Inspiration, because it is obvious that it's her faith that is going to be the main point, that is going to help her through whatever is coming.
Also, the descriptions of feelings and thoughts were very repetitive. The author restates many times how Sophie feels, or impressions she gets. I understand that the author might want to make sure that the reader understands, but it's a bit heavy-handed.