Is it wrong that I don't want my stepson at my baby shower?

I have my baby shower coming up in March. My mom and mother in law are planning it for me. My mother in law helped with my wedding and made everything about my step son(literally everything. Cake toppers, center pieces, etc) she oversteps her boundaries and my husband refuses to say anything to her, and if I do she's not going to like it!! I love my step son to death but, I didn't and don't want everything to be about him at my baby shower. I want my baby shower to be about my baby girl, not about how my step son is getting a sister, how he's going to do this and do that. I just know that if he comes my MIL will make everything about him, and that's not fair. This is my first born and I'd like to enjoy all of this, without being reminded about how Collin(my step son) is going to have a big sister, and Collin is going to be the best big brother and yada yada. I get that he is going to do all those things. But she doesn't need to make it all about him, because it should be all about my daughter at the baby shower.
UPDATE:
Some of you ladies are crazy! All I'm saying is this baby shower is not about him. And that's why I don't want him there. My husband feels the same way and has no problem with him not coming. It's actually not our Saturday to have his son, but I have a feeling that she(MIL) is going to ask his mother for him(stepson). I have included him in many many things. My wedding invites that I made had a picture of all three of us on it and we're written in Collins prespective(so he was inviting my guests to the wedding). I said vows to him also, at my wedding. We had a first dance together at my wedding. All of that was what I wanted. What I didn't want was pictures of him at each of my tables, mine my husbands and his initials on top of our wedding cake, etc. it was ok to a point. I will not say anything to her, she will just find a way to make what she wants happen and I'd rather just avoid the drama. 
And for those of you ladies who think "that poor boy" "I'd hate to have you as a step mother" etc. you have no idea what I do for this boy. So here, enjoy some pictures of me being so terrible to him!! 
😂