If I had a middle schooler that was very mature, or if I was aware that a child had been through some experiences similar to Maya Angelou's, I might share this book. I would want to read it first, however, and let the middle schooler know I was available to read/discuss it with them. If it was one of my students (as opposed to my own child), I would want to talk with parents about the content, and get permission before I gave the book to a child. Depending on school district policies, I might also want to clear it with my principal.
In general, I am not a big advocate of censoring books. At the same time, I definitely think that teachers need to be aware of kids' chronological, mental and emotional ages and stages as they help them select books. I worry when parents of kindergartners tell me that they are encouraging their five year olds to read three hundred page books, simply because the child can read the words. I worry when second graders read short chapter books with difficult content, e.g. SARAH PLAIN AND TALL, simply because of the length of the book. I worry when my high school son has to read CATCHER IN THE RYE because it's a "classic coming of age" novel. Even though kids can read and understand the words, sometimes, the ideas are just too big for them to wrap their heads and their hearts around. At best, they don't take much away. Worse, the book disturbs them or presents them with content they are simply unable to handle. Still worse, it turns them off to reading completely.
Hope that answers your question, Angela. Happy Reading in 2009!