For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Anne Frank: The Diary of a Young Girl does not fit the Three Act Plot Analysis. Since the contents of the diary regard real life events which were in no way planned, we don't think that analyzing the structure of her life events in the Three Act framework will help us understand the book better.