What is it with these freaking MILs?!?!

My MIL is adamant about throwing me a baby shower when I'm 38 weeks pregnant. She and my mom were originally planning a shower together but my MIL backed out. My mom is now throwing me a shower when I am 30 weeks pregnant, and the only reason my MIL wants to throw a separate shower is because she wants me to be "the most pregnant possible" and she thinks 30 weeks is too early. I am 100% uncomfortable with this idea and I think it's extremely rude to back out of co-planning a shower with my mom just because she thinks I "won't be pregnant enough." 
I mentioned to her that I don't want to have the shower that late because I don't want to be miserable at the shower and she literally said "we want you to be miserable. I need to show all my friends how big you are at the peak of your pregnancy." 
I'm not a damn museum exhibit. Jeez. 
It's nice that she wants to plan me a shower, but who is this shower really for? 
I'm just so pissed off about how she is treating my mom in all of this and how she refused to consider opinions other than her own.