Sure, but if in this case the number would have only indicated the month you have an issue way earlier than 100 actually, you already have an issue on month 13 when you would go back got 01 and now you are overriding the old one.
> It’s been about two thousand years since the number of months in a year has been increased.
What? What are you thinking of? The number of months in a year is always 12 or 13 in any calendar system because they start by reflecting the moon. If you mean the Christian calendar, it was fixed at 12 months to the year well over 2000 years ago. If you mean any calendar, it's probably been more like one year since the number of months in a year has been increased. 12 lunar months falls short of a solar year by about 11 days, so any given lunar calendar will generate an extra month about every three years, and there are lots of different lunar calendars.
(For example, the Chinese calendar occasionally repeats full months in order to keep the month of the year lined up with the season. Whenever this happens, there will be 13 months in the year, of which two share the same name.)
The ancient Romans claimed to have had a 10-month calendar [1], which is what I assume the reference is. Either that, or when month 6 got renamed August in honor of Emperor Augustus
> The ancient Romans claimed to have had a 10-month calendar [1], which is what I assume the reference is.
Well, in the first place (as you note), there is no reason to believe that claim - the ancient Romans never made such a claim, but the classical Romans made that claim about the ancient Romans - but more importantly even if it were true the months would have been added many centuries prior to "about two thousand years" ago. Nothing related to additional months happened two thousand years ago.
Given that 09 and 10 refer to months, that wont ever gonna be a problem. And if you want to differentiate them years too, you can prefix with 2025- or put them in a 2025/, 2026/ etc folder.
