Which AI is best to understand/convert to & from my alternative calendar system?

I generally do not use the Gregorian calendar for a special type of journal for myself I am creating. I use my own date system. Here is how it works:

I have replaced the year cycle with a month cycle. I call these months PERIODS. I started counting periods in July of 1999, when I was born. That period is called -198 (negative 198). August 1999 would be negative 197 (-197). There is no month/period called zero. I go straight from negative 1, to 1, 2, and so on.
July 1999 is -198 (198BC)
August 1999 is -197 (197BC)
...
November 2015 is -2 (2BC)
December 2015 is -1 (1BC)

January 2016 is 1
February 2016 is 2
...
December 2023 is 96
January 2023 is 97

And so on.

I tried to teach this to GPT-3.5 & Bard and both of them failed miserably. 3.5 got very close and was hit or miss a few times. GPT-4 seemed to understand but forgets after a few prompts.

Which AI would most likely understand this?

Please also note I want them to process a 100-page autobiography I have written about myself using my dating system.