Yes, that’s another good point. I had forgotten about that. Barry sure seems to have a lot of trouble remembering how old he is and when he was born and what day it is. Probably because he stays stoned and/or drunk from all the White House parties he keeps having. (Something like 3 per week?)
Being under the influence doesn’t make people forget their birthdays. It might cause people to mix up lies, though. He has two birthdays, the real one and the fake one.
This is what I think as well.