The relatives who visit twice a year are the ones who notice how much a child has grown. Everyone in the house misses it entirely, because they're recalibrating daily.
You live in the house with yourself. Whatever has changed this year is being measured by a gauge that adjusts as fast as the change occurs, which is why the honest report always comes from someone who has been away for a while.
If you want evidence, it's held in other people. The friend who says you seem lighter. The colleague who noticed you handled something you'd have dodged last spring. They aren't being polite.