Often when younger children have no one to play with when they are left behind as the school year begins, they are eager to go to school and be a part of what the others are doing. This is true of Scout.
In Chapter 2 of To Kill a Mockingbird, Scout recalls how she often spent hours in the tree house, looking over at the schoolyard through a telescope, "secretly sharing their misfortunes and minor victories." Unfortunately for Scout, her first day does not meet her expectations of school. Before the morning is over, Scout is brought to the front of the classroom and her teacher, Miss Caroline, hits the palm of her hand with a ruler before placing Scout in the corner. Further, Miss Caroline criticizes Atticus for having taught her to read improperly.
Like many precocious children, Scout is well-meaning, but when she tries to help her teacher, who is new to southern Alabama, by offering background knowledge on some of the children, Miss Caroline misreads Scout's intentions. She thinks that Scout is trying to undermine her authority, and she disciplines the girl. Thus, Scout ends the day miserable.
At last Scout would be entering the first grade.
I never looked forward more to anything in my life. (Chapter 2)
Atticus has stressed the importance of education to his children though he was home-schooled himself. Jem loves school and is an avid reader, and Scout has already learned to read--and write cursive. She and Atticus read together each night, and Scout looks forward to the great learning experience that awaits her. She greatly anticipates the first day though Jem warns her that "school's different." For Scout, it is an end to the loneliness and boredom that she must have experienced in past years while Jem was at school. She spent hours in the treehouse "spying" on the kids in the schoolyard through her telescope, learning their games and
... secretly sharing their misfortunes and tiny victories. I longed to join them. (Chapter 2)
Going to school would be the next step toward growing up for Scout. It meant meeting new friends, learning new things, and not having to spend as much time with Calpurnia each day. Sadly, her first day at school was not a good one, and the rest of the year "was no more auspicious." By the end of the year, Scout "could not help receiving the impression that I was being cheated out of something."