Numbers as Dates

When I turned 28000 days old, there was no way to turn this number into a date until I reached 28100 days old. At this point, it's possible via this stratagem:

28 - 1 - 00 --> 28th January 1900

There is ambiguity here because 00 could be interpreted as representing 2000 but I'll stick with 1900 for reasons that I'll make apparent. Yesterday I turned 28149 days old which converts as follows:

28 - 1 - 49 --> 28th January 1949

Hmmm. On that date, I was not yet born although I was a seven month old foetus. However, today I'm 28150 days old and this converts as follows:

28 - 1 - 50 --> 28th January 1950

Now by that date I had been born and was about ten months old. The interesting thing is that when I turn 30449 days old, this can be made to correspond to my birthday in the following way:

3 - 04 - 49 --> 3rd April 1949

There's ambiguity here because 30449 can also be made into another date:

30 - 4 - 49 --> 30th April 1949

All this requires that we admit to leading zeros when we want them, omit them when we don't and make choices that to suit ourselves when confronted with competing alternatives. In other words, flexibility is required. This process is not continuous. It works until I exceed 28999 since:

28 - 9 - 99 --> 28th September 1999

However, 29000 doesn't work and this number to date conversion only becomes possible again when I reach 29100 since:

29 - 1 - 00 --> 29th January 1900

With the leading two digits being 29, care must be taken with leap years and February. What happens with 29200?

29 - 2 - 00 --> 29th February 1900

Is the 29th of February 1900 a valid date? It is if 1900 were a leap year but it's not since it's not divisible by 400. If we interpret the date as 29th February 2000 however, then the date is valid since 2000 was a leap year. Sticking with the twentieth century convention, valid dates only arise with 29204, 29208, 29212, ... , 29288, 29292, 29296.

After reaching 29300, there's no problem with the leading two digits being 29 and things will be fine until I reach 30000. The number to date conversion will kick in again at 30100 and I'll reach 30449 without any gaps. All this is hardly serious mathematics but fun nonetheless. 

In all of this, I've adopted a day - month - year format switching between DD-M-YY and D-MM-YY as it suits me. This works well whereas other formats lead to lots of inadmissable dates and aren't as much fun.