Disclaimer: This has nothing to do with backgrounds from DND5.
It happens a lot that the story you create for your character sometimes is not as in point with what happens afterwards in-game. If you are a Lvl 1 Warrior you maybe can say you fought in the frontlines of a bloody war, and now are a retired mercenary.
Then you end-up losing to a bunch of rats the GM threw your way because the ceiling was too low and you forgot your matches.
What I want to know, is there a table/resource that has some indicator of what you may have accomplished when creating a character of a specific level?
That way I won’t embarrass myself narrating when I defeated a lich in my Lvl3 Ranger backstory, just to be inmediately destroyed by two goblins and their pet wolf in my first encounter.
I don’t mind DND/pathfinder responses, even when the power level may differ between the two, and even between versions, I’m more interested if the resource itself exists, or how to create one.