Being the oldest kid means you learned resilience before you learned the word. You still get to set some of it down.

Responsibility arrives early for the eldest, often without anybody deciding it should, and competence gets built out of necessity. The useful part is real and so is the cost: a habit of managing, of not needing things, of assuming it falls to you. Habits formed at eight do not expire on their own. You are allowed to review which ones you still want.

Find one thing you have been handling that somebody else could carry, and hand it back this month, even if it goes slightly worse without you. Let yourself be looked after sometimes. Being capable does not oblige you to be in charge forever.