Just wanted to share a brief, but positive update. I ended up hearing from my brother, I guess he was just doing his thing and wants nothing to do with this fight between me and mom which I totally get and am fine with. His relationship with her is very very different than mine and hers. He said he thinks the way I approached the conversation with mom was really dumb which bugged me a fair bit. Told him I disagree it was totally reasonable and I approached it in the calmest most positive way possible I am over tip toeing around whatever might set her off in any moment.
I explained I am done with her completely, she is blocked on everything and he said that's fine I get it moms a retard. (his words not mine)
So while not totally what I would have wanted, he and I are ok and I am happy about that. He's gonna finally move far away from her in about a month and a half, so I hope that will give him more perspective.
I left that family discord, made sure she is blocked everywhere. and my fiancée blocked her on LinkedIn since she was trying to add her there.
Wedding will have security and they will have an image of her and a description so she wont be able to get in. (its also far from where she lives, cant drive and wont get on a plane) My father and groomsmen are also aware and can handle it if she does show and get past security somehow.
Thanks everyone here for reassuring I am not crazy, did nothing wrong and am doing the right thing. I am doing much better now. Still a little up and down for sure, but overall much better.
I am just so excited for the beautiful peaceful life I am starting with my wonderful fiancée and thankful to my step mom and dad for giving me support and being the shining lights of my childhood.