The Secret School by Avi, 2001.

The year is 1925, and what 14-year-old Ida Bidson wants most is to graduate from her community’s small, one-room schoolhouse so that she can go to high school in a nearby city.  She dreams of becoming a teacher when she grows up, and she knows that she can’t do that without more education.  The problem is that, in her rural community in Colorado, not everyone thinks that higher education is important, especially for girls.

When their teacher’s mother becomes ill toward the end of the school year and the teacher has to leave, the man in charge of the local school board, Mr. Jordan, doesn’t want to bother to hire a new teacher to finish off the year.  In fact, it seems a little dubious about whether they’ll even get a new teacher in the fall.  Ida is crushed because, without a teacher, she can’t graduate this year as planned, and she had just about persuaded her parents to let her attend high school in the fall.  Her friend, Tom, is in a similar position.  More than anything, he wants to work with radio, the latest technological development of their time, and he also needs to attend high school.  (So far, he’s just been teaching himself by reading Popular Mechanics – the magazine started in 1902 and is still in circulation today.)  However, Tom comes up with a plan that could help everyone: What if Ida becomes their teacher?

Ida knows that there’s no way that Mr. Jordan would actually hire her as the new teacher.  Everyone knows that he’s a miser and that a large part of the reason they’re not getting a new teacher is that he doesn’t want to have to pay for one.  Besides, what school board would hire a 14-year-old girl who hasn’t yet graduated?  After discussing it with the other children, they make the decision to keep their school open secretly with Ida as their secret teacher.  Although Ida confesses the truth about what they’re doing to her parents, most of the others don’t, figuring that they’ll wait to tell them when the school year officially ends in another month.

Although it’s a daunting challenge, going from student to teacher while still continuing her own studies, Ida sees it as the only way to get what she wants.  She does her best to act out the part of teacher, telling her friends to call her “Miss Bidson” when she’s teaching instead of “Ida”, giving them their assignments to study, and checking their work. 

Most of the other children agree to her terms as their new, secret teacher, although one boy, Herbert, deliberately gives her a hard time.  Herbert’s future ambitions don’t include higher education, and he was originally looking forward to having an early summer break.  At first, he delights in trying to push Ida, to see how she’ll deal with him as a discipline problem.  Ida partly earns his cooperation by pointing out with him that their secret school is voluntary, that no one is making him come, that they had all voted to make her the teacher, and that if he makes problems for the other students, they can also vote him out of the school.  The thought of being rejected by his friends for making problems keeps him more or less in line.

Then, a woman from the County Education Office, Miss Sedgewick, comes to the school and finds Ida teaching there.  She is the one who administers tests to graduating students, and she has come to ask how many students will be tested this year.  Ida is forced to admit her circumstances to Miss Sedgewick.  Miss Sedgewick is surprised to discover that Ida is both teacher and student and says that she isn’t quite sure if she can give the exams if the local school board has officially closed the school.  She leaves, promising to look into the matter.  What she eventually tells them is that they can keep the school open with Ida as the teacher, but in order for the children to get credit for their work, they will all have to take exams at the end of the year, not just Tom and Ida.

As the end of the school year approaches, Ida does her best to prepare the other children for the exams and thinks about how her relationships with them have changed.  Tom, her best friend, has become more her student and less her friend, which feels uncomfortable to her.  She also has her own studying to do if she hopes to pass the exams herself, which is difficult both with her teaching work and the work that she must do on her family’s sheep farm.

Then, Herbert’s father, who doesn’t value education at all and just wants Herbert home to work their farm, finds out what they’re doing and gets Mr. Jordan to shut the school down for good.  Ida feels like all her dreams and hard work have been for nothing.  However, a talk with Herbert changes her mind.  Herbert knows that his father fears his education.  Herbert’s father is afraid that Herbert will look down on him for not having as much education or that Herbert will want to leave him.  Herbert admits that he’s been very unhappy at home because his father is a bitter, angry man who doesn’t treat him much better than he does other people.  Herbert has actually learned more than he pretends at school and really does have plans to leave home.  Herbert also tells Ida that his father and Mr. Jordan are planning a secret meeting to close the local school permanently, purposely telling only people they know will agree about it, not local people who value education. 

Knowing about the secret meeting gives Ida’s parents, as well as other parents in the community who support their children’s education, to show their support for their children’s hard work.  Faced with their opposition, Mr. Jordan agrees to let the school remain open while the children take their final exams.  Ida not only does better on the final exam than she had feared, but she finds an ally in Miss Sedgewick, who will help her fulfill her wish to attend high school and become a real teacher.

The book is available to borrow for free online through Internet Archive (multiple copies).