Is cousin sister discriminating you cause you're not attractive is common?

I never want to go to mamaghar for this reason. Cousin sister used to be so happy when my brothers are around but they just ignore or try their best to not talk with me cause I'm ugly.

They video call their friend and show my brother to them and laugh with friends about how attractive he is.

They totally cut contact from me but they keep in touch with other cousins and my brother.

I always wanted a sister and thought they would feel that void. But serisously I need to be attractive for that too?

Is this common thing? I can't talk with them.