I am forty-four. I know this factually. But there is a version of me that exists somewhere around thirty-one that I keep accidentally inhabiting.

I notice it in specific ways. I am surprised when I can't stay up as late as I used to. I am surprised when my body takes longer to recover from things. I am surprised, sometimes, to catch my reflection in a way that registers - the gray, the line across the forehead - as if my internal image of myself is running on a delay. The image is not wrong exactly. It's just several years behind the current version.

I've been trying to understand when this internal image was set. I think it happens in your early thirties - that's when you arrive at a self that feels like the real one, the finished one, the one that will persist. And then the body continues aging past that fixed image while the image stays. You become a person looking at a photograph of yourself from several years ago, and the photograph is your sense of yourself.

There's a particular shock that comes at unexpected moments. Realizing a reference I think of as recent is fifteen years old. Meeting someone I knew as a child and understanding they are now a full adult person with their own adult life. The math doesn't match the feeling. The feeling is always younger than the math.

I'm not distressed by aging exactly. It's more the slight dislocation of being a specific age and simultaneously not being that age, of carrying a self-image that is technically outdated and has no mechanism for auto-updating.

How old does your internal self think it is? Is the image current, or is it running behind?