Lord Dunsany 
If 

"If" is a short story written by Lord Dunsany that explores the concept of time travel and the consequences of altering the past. The story revolves around a middle-class British man who receives a valuable gem from a Persian beggar that grants him the power to travel back in time. Despite the objections of his wife, the protagonist decides to use the gem to correct a minor slight that he experienced from a railroad attendant in the past. He believes that by rectifying this small injustice, his life will continue as it did before with no major changes. However, upon returning to the present, the main character is no longer the same man he once was, and his relationships with his family and friends have been irreparably damaged. The story raises questions about the consequences of altering the past and the dangers of trying to change one's fate. It highlights the importance of accepting the past and moving forward, rather than trying to undo the mistakes that have already been made. Hence, it can be read by people of all ages and it will not let you down!