What is the story mainly about

Ramona Quimby has a vivid imagination and alot of spunk, which sometimes earns her the rather unfair reputation of being a bit of a pest. Of course, she doesn't mean to be a pest. Circumstances conspire with each other to make her seem that way. Now that her father has gone back to college, and her mother is working full time, it's been decided that Ramona is grown up enough to make her own way to school (after all, she is eight). Ramona is going into third grade, and is also going to a new school, Cedarhurst Primary, where she and her friends will be the oldest kids there. Because her sister Beezus is going into high school, Ramona is going to be riding the school bus every day.