I want to find my long lost big sis!!!!!!!!!!!!!!?

ok so i have a big sister but i dont even know if she knows about me. i was put up for adoption when i was born and she was 4 years old. i just found out about her and really want to find her bad!!!!!!!!! but im only 16 and my adoptive parents wont let me until im 18! somebody please please please help me!!!!!!!! i know shes like 20 or 21 and born in new orleans. and my real moms name is like sherri or something like that and my sisters name is like kristi rolf or something. and my adoptive parents changed my original name from haley to my name now which is kasey