Types Of Impossible Goals

Hello! I would like my Impossible Goal to be confidence/ feeling good about myself/ just being my true self and not caring what other people think. I have failed at this goal for as long as I can remember despite being successful on paper. Can this be my goal? Or do the goals have to be more specific (make x dollars, lose x lbs)? I am trying to brainstorm ideas for concrete milestones to show I have reached that goal, but I am only coming up with feelings, which aren’t concrete. Thoughts?