With a still image often the quality of a person's skin is the only giveaway, and when that is the case I'm remarkably accurate most of the time. So I'm skeptical there's much one can do, and people's skin seems to age at roughly the same rate.
Tiny ears - teenager. Huge ears - senior.
> This study supports the view that as people age, their ears get larger, particularly the ear circumference, which increases on average 0.51 mm per year. This enlargement is likely associated with aging changes of collagen
So they do get larger with age but not due to growing, but rather the typical aging of the skin + gravity tends to result in the ears enlarging in diameter.
Do they wobble to and fro?
Can you tie them in a knot?
Can you tie them in a bow?
Can you throw them over your shoulder like a continental soldier?
Do your ears hang low?
The famous image of the trucker who had the sun on the left but not right side of his face shows the cumulative effect of sun damage: https://www.cbsnews.com/news/trucker-accumulates-skin-damage...
Normal cases are less extreme but this shows what happens if you do/don't protect against the sun.