What does that mean to you? And how do you learn it? What if you’ve gone your whole life not knowing who you are? Where do you begin? Where do you start? What do you ask yourself? What kinds of questions do you ask yourself? Etc...
It's emotional subjective analysis, based on what others think of you within a social construct. I'd concentrate on your self worth/value first and foremost. Er on the selfish side, do and be what makes you happy, what makes you feel good ignore others, become confident within the limits of your abilities, then maybe consider what others think of you, but not too seriously.