My mom mixes up my birthday and my sister's birthday. She cant miss up the other two sisters, both were born on the 22nd just different months.
My sister's is on the 17th and mine is on the 19th so she frequently misses my sister's and is early for mine. Doesnt bother me, aggravates my sister to no end.
But then I cant keep my mom and my grandmother's straight. One is July 5 and one is July 6. Just a few months ago my mom was picked up unconscious by the squad and in all the confusion, I gave them the wrong birthdate....screwed up things at the hospital for days.