I have read a novel twice called I Am the Messenger by Markus Zusak and I believe it was essential into forming my passion of becoming a teacher.
But would that work? The book is relatively unknown, so I would have to write a summary in order for the admissions readers to understand how it influenced me and then explain how it did.
I don’t know if I should do this or not… Thank you if you read this and reply! 
You can try it; it’s all about saying all that needs to be said about the book, and no more, so that you can use the majority of your essay to focus on yourself.
I think you would be spending words on explaining the backstory that might be better spent explaining why you would be a good fit for the school.
Could you choose one key quote and use it instead?
But now, of course, as a teacher, I’m curious about that book!
I ended up not using it.
I wanted to do “I Am the Messenger” by Markus Zusak.