Monster in law 😡

My mother in law is trying to take over everything! I told her that I want to be involved with MY baby shower (pick out colors, decorations). She doesn’t want me to do anything. She doesn’t want my family apart of it either. She only wants to do one for her side of the family. I want both of our families to come together that day to celebrate the baby and I also want to pick out the decorations and I want to decorate. I LOVE to decorate. Every request that I have she tells me “no” she even told me “sorry but I am throwing the baby shower and that’s how it’s going to be”. I don’t know what to do. I am so frustrated with everything. This is my first child and I want to be involved as much as I can be. What would y’all do if y’all were in my position??