Chicago isn’t a city for wimps. While her teenage peers hung out at the mall, Josie Bellini waited tables. While other kids went to the movies, she took care of her sister. “I’ve just turned 26. It wasn’t that long ago, but it feels like a lifetime. It feels like someone else’s life.” Bellini made choices that some of us don’t have to make. On the girl in math class who helped her slog through lessons, “It was kind of a strategic friendship at that point, and then we really became good friend...