Approximately when does the story begin?

The story that seems to begin after an interesting divergent beginning (that goes into history about 10-20 years and almost 100 years ago...) sounds like it is 1932 or 1933. In the first line of the novel Scout tells us that this is the story about Jem being 13 and breaking his arm. We know that he's 13 by the end of the novel. By the end, Ewell looked for the job from the WPA (1935).

When the kids meet Charles Baker Harris (Dill), the introduce themselves and their ages. Scout's 6 or almost 6, and Jem is 10. The trial, is two summers later in which Atticus refers to 1935. This leads me to believe it starts exactly in the summer of 1933.