A title tells people where you sit. Your work tells them whether you belong there.

Titles are issued and work is demonstrated, which is why the second one is believed. Being made captain, prefect or shift lead gets you a label and about a week of benefit of the doubt. After that, people decide whether you earned it by watching what you do with it. The label can be taken back; the competence stays yours.

If you have just been given something, spend the first fortnight being useful rather than official, starting with one part of the job nobody wants. If you were passed over, do the work anyway, because that is the part they cannot award or withhold.