Help!! How do i handle people inviting themselves to my wedding?

I have a cousin who assumes that she is invited to my wedding and has been texting me wanting to know the date and details. I know she suspects the wedding is coming up soon and realizes she has not received an invitation. I haven’t posted wedding details on social media. Unfortunately, I cannot use the excuse that it is a small private wedding because we have invited over 200 people. She and I live in different states and although she is a little over an hour away, we do not hang out together unless it is a family event. Our interactions in between are only on social media. The reason I am not inviting her is because she made some rude comments on a social media post I had made and seriously offended my FH, leading me to delete my post (my post was a pic of my FH sitting across the table from me on date night and he was on his phone—not super flattering, but he was doing a social media check in that we were having dinner at a new restaurant and he was with me, which was the same thing I was doing with my post. We stay off of our phones the majority of the time). She has never met him and her banter was completely out of line, accusing him of ignoring me for his phone (he wasn’t) and threatening him if he continued to “ignore” me in spite of my numerous comments stating what was really going on.
I’m trying to figure out a way to be gentle and polite and telling her that she is not invited to the wedding. Unfortunately, the weekend before my wedding I have a family reunion and she will definitely be there, as will a number of people who I have invited to the wedding. I am afraid she’ll confront me there or that one of those folks will tell her the details and she will crash my wedding. I want to go to my reunion......how do I handle/avoid the ensuing drama? Advice/Perspective much appreciated.