The short answer is: younger than most people realize. There’s no law that says you have to wait until you’re 18 to have credit history — the rules are about what you can apply for on your own, which is different. A 13-year-old can be added to a parent’s credit card as an authorized user and start accumulating credit history right now. Whether that’s the right move is a separate question, but the “you have to be 18” assumption is wrong.



