Being underestimated stings. Being overestimated is worse, because now you have to keep pretending.

Low expectations are uncomfortable and come with room to move. High ones, built on something you have not actually got, come with a maintenance bill: every conversation managed, every gap hidden, every question steered. The pretending is exhausting in a way that being doubted never is, and it gets heavier the longer it runs, because the correction costs more by the week.

If somebody has you wrong in the flattering direction, correct it early and small. Say the one true sentence about what you have not done yet. The relief of not performing is immediate, and people respect the accuracy more than the reputation.