You’re beautiful because that is what God made you. There is no comparison to others, no other standard that says otherwise. You are truly beautifully and wonderfully made!
“So God created man in his [own] image, in the image of God created he him; male and female created he them” Genesis 1:27.
“I will praise thee; for I am fearfully [and] wonderfully made: marvellous [are] thy works; and [that] my soul knoweth right well” Psalms 139:14.