Age doesn't determine a coin's value. I used to be a coin collector when I was young and the case of the 1913 Liberty nickel is that an employee of the mint had made five unauthorized 1913 Liberty nickels which that year was being replaced by the new Indian head/Buffalo nickel design after 30 years. The mint never intended to make any 1913 nickels with the old discontinued Liberty design but even though they were apparently unauthorized, they were legitimately struck at the mint and were legal tender which is why they became legitimately valuable.

Obviously when hundreds of thousands of a particular coin exist it's not going to be that valuable regardless of its age as opposed to something where only five were made to begin with.

Interestingly, a 1913 Liberty nickel also figured in the plot of an 1978 episode of "The Hardy Boys/Nancy Drew Mysteries" called "The Mystery Of The Avalanche Express". TV writers knew it was a great device to fall back on for storytelling!