Age is just a number...

Conversation between mom and I last night.
Mom: How old am I turning, is it 45 or 44?
Me: 44, I am pretty sure. See you had me when you were 21, so that's what the difference always should be, and if you were turning 45 it would have been 23 years.
(Meanwhile in my head I am trying to figure out why the difference turns out to be more than that at the moment. Coming to conclusion that it evens out during the year because our birthdays are in different months (Seriously?? No logic in that!) I hear my mom saying:
Mom: That's right, you are turning 23.
Me: WHATTT??? 23?? I thought I was turning 22.
My question is, if I forget my age by 23, what will I be able to retain by 40? Stress is powerful.