I was confident and wrong. That doesn't necessarily mean I had false confidence

Well... this can get into philosophical territory. It seems cleanest to describe confidence in something wrong as "false," although it may have been the best possible answer for you to give at the time. Saying "the confidence wasn't false because it was from a systematic bias" seems like it opens up a host of problems.

An idea that seems useful here is "being predictably surprised." You can't stop yourself from being surprised without omniscience, but you probably can stop yourself from being predictably surprised with a well-trained outside view. If the question had asked about, say, the median price of a meal at a restaurant, and you hadn't frequented restaurants in 10 years, you would probably have very low confidence in the specific price you remember, since you expect things to have changed in 10 years; a similar approach would have worked here. ("Well, Starcraft was super popular, but it's been a while; let's say Starcraft with, say, 10% probability.")