Why is Scout confused when she gets in trouble the first day of school?

Scout gets in trouble for knowing how to read because the teachers are advised to teach in a new way. Also, she gets in trouble when Walter Cunningham doesn't bring his lunch and the teacher gives him a quarter for lunch to be paid back tomorrow. Scout, with knoweledge of the Cunningham family, tells the teacher he is poor and can't pay back. The teacher gets furious and calls her to the front of the room to be whipped by a ruler.