Your Character’s Age Doesn’t Matter (As Much As Your Readers Think)

If your readers ask the age of your character, they’re really asking for something else: What makes this character special, unique, believable, and human? Age, as they say, ain’t nothin’ but a number.
In every workshop I’ve attended—at the undergraduate level, in my MFA studies, and now at the BWW—I’ve seen discussions of stories that prompt this question: “What’s this character’s age, exactly?”
This question is a red flag. The warning: You haven’t provided enough detail about your character. The reader is making an honest attempt to understand your character, but can’t, and is unconsciously attempting to forge a shortcut. Tell me this character is ten years old, they say, and I’ll bring what I know about ten-year-olds to this story.
The problem with this attempt is that all ten- or whatever-year-olds are different. You can’t pin believable characters down with only as broad a description as “age.” Give readers insufficient detail, they’ll wonder how old your character is; give nothing more than an age, and you’ll give them license to imagine too much.
Some situations demand that you reveal your character’s age. For example, a character’s actions may carry more weight if the character is not a legal adult. This, however, is generally speaking more important to plot than character development.
One solution is to reexamine your character’s place in the story. What can you show us about this character’s life? What does s/he say to other characters? How are they controlled (in the case of a child/parent relationship) and how do they respond to that control? What level of responsibility do they carry? Ask more questions about this character’s life; come up with answers in your story.
When has character age been a problem in your writing? How did you solve it?