boyfriends sister 🙄🙄🙄

I got into a argument with my boyfriends sister a while ago. I was more so telling her how I feel  and she got offensive and said very mean things to my face. I left , she called me and left me a nasty VM. & texted my boyfriend some very very rude things about me. Now a few months later, my baby shower is in a week and she is all of a sudden trying to talk to us about the situation. My boyfriend and her talked and supposedly hashed out their issues because they got into a very heated argument after she said mean things about me . Now she wants us all to sit down and talk and apologize. I'm very upset about that because I feel that I did nothing wrong. When she start attacking me in person , I walked away. When she called to argue with me after I left , I didn't answer or respond in anyway after she left me a nasty VM.  She's is 10 years older than me and acting very childish saying I started it and yelled at her and that's definitely not true , my boyfriends mom was standing right then and her kids . I would NEVER yell at her. I don't feel like I should have to apologize because I have acted like an adult since day one. I feel She is honestly just trying to "fix" things so she can come to my baby shower cause this is her first niece . My boyfriend is the only sibling she has and it's his first /our first child. And I honestly don't want her there especially cause now I'm finding out she's telling everyone I yelled at her and that why she said the messed up things she did. Ugh I don't know what to do. Help me.