Being tall doesn’t make you a better cosplayer.
Being short doesn’t make you a better cosplayer.
Being skinny doesn’t make you a better cosplayer.
Being chubby doesn’t make you a better cosplayer
Being the “correct race” doesn’t make you a better cosplayer.
Being the same gender as the character doesn’t make you a better cosplayer.
Nothing makes you a good cosplayer but you and the effort you put in.