Naturally, the quote is a J. K. Rowling original. :-)
Whenever I feel discouraged about someone not "getting" who I am as a person, I remind myselfthat they are not me. I am not them. It's okay to be different. Don't stop doing what you love or being who you are because someone doesn't understand it.
Believe in your magic, even if others don't. They just can't experience it for themselves.