Why always me ?

I don't understand ... today is my sis birthday ...I'm sooooo happy for her . and we are so happy together we sang birthday song . and then she went to tuition . and I'm at home. suddenly I recieve a call from my friend. then he said he and some of his friend wanna go to secret recipe to have a cake to celebrate. and I ask my mum ,my mum said that we are busy and it's danger to go at night !!! so I he call again .... I answer and told him I"M NOT GOING !!! I told him I said we are busy . so then i went to eat dinner . then I call another of my sis friend, I told her we are not going i pass the phone to my mum and she told her my sis can't go for some reason!aster that she come back .... then she said I DIDN'T TOLD MY FRIEND MY SIS CAN'T GO . I told them it's like my wrong . the others didn't have wrong !!! what's the matter ?...so no fair ~~~