I think "To Kill a Mockingbird" was a solid choice for required reading, but I always found it more impactful when read later in life. As a kid, the themes felt abstract. It wasn't until I had some real-world exposure to injustice that the book really clicked. Maybe that's why it's a classic—its message grows with you. Not sure if it's the best for 13-year-olds, but it's definitely memorable.