What to do if my mom is there?

Backstory first. I grew up being raised by my Dads family. My grandmother took on the role my mother didn’t take. For years I would see her on weekends if I saw her. She remarried and her second child ended up living with their grandmother as well. She remarried again and those children went through it. I always stayed in contact and had visits throughout my teens. I become a mother and she suddenly started coming around more because of my child. I also think her boyfriend at the time pushed her to see us more. Fast forward I am now married and have 3 more children. Years back I came to realize upon taking on more responsibility with my children that that dealing with her visits were too much. She would drink ( a big priority for her), she had no license from drinking, and I began asking myself if I really wanted her around my children. Was it worth it? I noticed during her visits, she would be happy at the beginning and maybe bring gifts for the kids, then she would seem annoyed and ready to haul ass back to her home state. I turned down a visit due to having to drive halfway to pick her up and told her I just wasn’t up for it. After, she wouldn’t respond to messages or answer calls. This happened throughout my life where she would just quit answering calls and then all of a sudden she would pop up like nothing happened. This time was different for myself and I found myself just not caring. I realized she had not been the mom she should’ve been throughout my life. Or any of her children really. It strained the relationship I have always had with her sister, my aunt. Now my aunts daughter is getting married. I haven’t seen them in 4 years. Before that we weren’t invited to Christmas etc. I feel like the right thing to do is to go to the wedding but… I really don’t want to deal with any of it. By no means am I scared to voice how I feel to any of my mothers family if it’s brought up, Im not scared to casually say hello or even not say hello if my mother is there. I just don’t want to ruin anything for my cousins day if someone mouths off to me. Opinions welcomed