People use it both ways. I use it more like you but the other way of still counting up is also very common. Almost everyone agrees the day is still their birthday in a sense, it's just whether people say "their 100th birthday" or just "their birthday" after they have died
Shaky_Balance t1_j22indn wrote
Reply to comment by MattoSensei in Stan Lee, 1987. Today is his 100th birthday by BlackMoldComics
People use it both ways. I use it more like you but the other way of still counting up is also very common. Almost everyone agrees the day is still their birthday in a sense, it's just whether people say "their 100th birthday" or just "their birthday" after they have died