What three mistakes does Scout make on her first day of school and why do they make Miss Caroline upset?

Scout makes several mistakes which get her into trouble on her first day of school. The first mistake Scout makes comes after she reads aloud in class. Miss Caroline then criticizes Scout's father for teaching her how to read, and Scout responds by telling her teacher that nobody taught her to read. Scout comments that Jem told her that she had the ability to read at birth because she was a "Bullfinch" who was swapped at birth. Scout says Miss Caroline thought she was lying and told her not to let her imagination get away from her. Scout naively believed her brother and realizes her explanation "annoyed" Miss Caroline.
The second mistake Scout makes comes after recess. While Miss Caroline is holding up flashcards with beginner words on them, Scout gets bored and writes a letter to Dill. Miss Caroline catches Scout writing the letter and tells Scout that her father needs to stop teaching her how to write. Miss Caroline is clearly offended that Scout is not paying attention to the activity.
Scout's third mistake happens when she attempts to explain why Walter Cunningham will not accept Miss Caroline's quarter to buy lunch. Scout assumes Miss Caroline is familiar with the Cunninghams. Scout tells Miss Caroline,

You're shamin' him, Miss Caroline. Walter hasn't got a quarter at home to bring you, and you can't use any stovewood (15).

Miss Caroline is shocked at Scout's response. She immediately gives Scout several pats on the palm of her hand and tells her to stand in the corner as punishment for her behavior throughout the day.