When did 6, or above average, become an insult?

I don’t know your background (religious or nationality), but it does appear that your mother uses shame to make you feel inferior. Brene Brown has podcasts,videos, and Ted talks about this subject that you may benefit from. I think you understanding what makes you happy will make your life so much more fulfilling. Express yourself in your appearance and surround yourself with people who bring you up. Just because someone birthed you does not mean they deserve the right to destroy you emotionally.