Does age make you stronger or weaker in the Avatar universe?

It’s clear during zukos fight against the red lotus he was barely keeping up, yet bumi was taking over his whole city at the age of 112. Maybe it’s because zuko didn’t train much during a time of peace? Idk I feel like zuko is the type of person to be ready for anything. Toph was still a gangsta at her old age when she took down those mechs so maybe it’s a earthbender thing

It’s clear during zukos fight against the red lotus he was barely keeping up, yet bumi was taking over his whole city at the age of 112. Maybe it’s because zuko didn’t train much during a time of peace? Idk I feel like zuko is the type of person to be ready for anything. Toph was still a gangsta at her old age when she took down those mechs so maybe it’s a earthbender thing