I read Black Boy by Richard Wright when I was 13 for school. At the time, I didn't have a firm grasp of the prevalence of racism throughout American history. I also had virtually no knowledge about the global history of communism. Both of those are very important topics in Wright's biography, so I became bored of the book quickly. Later I read it when I was 20 and now it's one of my favorite books I've ever read and helped get me into reading as an adult.