When we, as players, start rolling up characters, we all approach our character’s personality a bit differently. Sometimes you choose class based on what sort of person your new character seems like. Sometimes details of personality start to form when you choose their background. And, more often than I’d expect, our characters turn out differently than we’d imagined once we actually begin play.
It’s important to explain why your character is an adventurer within their backstory. Adventuring is dangerous, and it’s not an especially secure way to make a living! So why is this character you’re making going down that route?