You are sitting on the floor because the bed is already disassembled, leaning against the wall, and there is a rectangle on the carpet where it stood for twenty years, a paler patch the vacuum never reached. You keep looking at it. You are thinking the room feels smaller now, or bigger, you can't decide which.
Take the tape measure back out of the box. Not to measure anything. Just to open that door frame one more time, the one with the pencil marks climbing it, the little dates in your mother's handwriting getting fainter near the top where you finally stopped growing. You are about to paint over those. I know. You will do it, and it will be fine, and the new people will never know a child was measured there on birthdays.
Here is the thing I can tell you from here: you will not remember the boxes. You will not remember which car you loaded or how the mattress wouldn't fit or the argument about the desk. But you will remember the sound this room makes when it's empty, that particular hollow echo of your own footsteps on bare floor, and you will hear it again in every empty room for the rest of your life.
Sit a minute longer. You're allowed. The truck isn't leaving without you.
Before you tape that last box, go stand in the doorway and look back in. Not to fix it in memory, you couldn't if you tried. Just because it was yours, and it was good, and you didn't know yet how rarely a place gets to be entirely yours.
Then turn off the light. You know exactly where the switch is.
You always will.