at his or her age
Tom est mieux que moi à son âge.
Tom is better than I was at his age.
Comment peut-on mener cette vie à son âge ?
How can someone lead this kind of life at his age?
— Burning (2018)
À son âge, c'est d'un père qu'il a besoin.
At his age, what he needs is a father.
— Faute d'amour (2017)
Mais à son âge, nous ne devrions pas prendre de risques.
But at his age, we shouldn't take any risks.
— PIKU (2015)
À son âge, je travaillais depuis trois ans !
At his age, I’d already been working for three years!
— Amarcord (1973)
Elle devrait être plus avisée à son âge.
She should know better at her age.