Well, until I was in my 40's I celebrated my birthday on the 26th. Even had a birth extract showing the 26th when I got married.
It was only when I applied for a passport and was required to get a copy of my birth certificate that I was told that that wasn't correct. They had a hand written note saying I was apparently born on the 22nd.
They suggested contacting the hospital where I was born to confirm but the hospital had no record....BUT...there was a record of mum being admitted to hospital on the 21st so I figure the 22nd is probably right...but, just in case, I celebrate both days...
And yes, I hung it on mum for not knowing the correct date of my birth over all those years...