How important are your characters’ birthdays?
Is there a certain religious celebration that comes with a certain age? Perhaps your protagonist must pass a test on their birthday before they “come of age” in their society? Maybe your antagonist had failed their test, stirring up bad feelings?
Harry Potter turning 11 way back in the Sorcerer’s Stone marked one of the most important turning points in his life — finding out he was a wizard. Many YA novels tend to have sixteen be an important birthday for the protagonists and Chosen Ones.
A handful of my protagonists’ ages tend to be, “Ehh, they’re probably in their early to mid-twenties,” and I leave it at that until the characters’ age needs to be concrete. Ages, of course, can be very helpful when figuring out a character’s mentality and physical limits.
How much time do you put into figuring out a character’s age?