How do i handle this HELLPP :(?

okay, so me and my cosine got into a huge fight and to make a long story short we both made mistakes and in the end i was the one to say sorry lets fix it. ahe tried befor but she didnt say lets fix it she said lets just barey talk....that hurt because we were like sisters and it wasnt even over a huge fight but anyway im just like fine get past it and i wanted to fix it completley not barley talk, she said no and never apologized and is now ignoring me. i didn't even do anything bad so anyway if she wasn't family i wouldn't care but she is and there are a LOTT of big bdays coming up and im sure the family will have a party...she is more popular so to speak with the family because she sees them more then i do so when we go to a family event what do i do? she hates me and we usually are stuck like glue its going to be torture how to i act. its hard to ignore it...any advice?