You don't know what epoch dating is either, do you? It's okay if you don't. It's a thing for data base administration. An example you can go look at is Amazon. Amazon uses the UNIX system, which sets the start date and time at Midnight on January 1st, 1970.
How they use it is to determine when you searched for something. So, if you search for a hat or anything, part of the URL amazon creates includes a long string of numbers that are the exact seconds it's been since midnight, January 1st,1970 and when you typed that search in Amazon.
Why do I bring that up? Because the social security system uses the ancient COBOL system. Why is that important? Because the creators of COBOL set the epoch start date to midnight, May 20th 1875.
Why that date? Because that's the date the Convention du Mètre was signed in Paris. And if the DoD commissioned COBOL in 1959 and it was created in 1960, why did they choose that date instead of 1960? They were being nerdy and thought it would be fun.
So, why do they pick specific dates and times as a start date? Because not everyone uses the same calendar or even the same dating system within that calendar. Like how Europeans date things by day, month, then year and Americans date by month, day, year.
That way the systems all know the date and report that information to the user in the format they're familiar with.
So, when someone tells you that there's a massive amount of people on the social security system that are over 100 years old, you automatically know they don't know how epoch dating works. And if you're thinking, "Well, Elon is a super genius who created paypal, tesla, and space X, this seems like a thing he should know."
And you'd be right if he was a genius who created those companies. But he's actually a nepo baby who used generational wealth to buy his way into more wealth.