Yeah, your last guess is right. Your score is just a quick reference guide for a lender to see how risky it is to lend you money. If you've been borrowing money and paying people back, you're low risk, so you'll have a higher score. If you've been borrowing money and not paying it back, you're obviously high risk and will have a low score. But if you have no history of borrowing money, you're an unknown. And unknown is risky. Thus low score. Still, worth checking your report to see if anyone has been using your identity to borrow money irresponsibly, but I wouldn't be surprised if you just found it to be empty with no errors.
