Is it reasonable to be offended by this?

So my SIL is pregnant with her first baby. She shamelessly uses the pregnancy card all the time just to be blunt and straightforward in a rude way and she’ll be like “I’m pregnant so I can say that.”

Her baby shower is on Sunday. I was invited with my 3 daughters. 2 of them are 5, and super excited about having their 1st cousin/new baby around.

Today, 2 days before the shower, she had her husband call my husband and say “***** feels like your kids are going to take the spotlight off of her so she asked me to watch them with you during the baby shower.”

Our kids are part of the family, pumped about the baby shower, want to be included, and want to be close to their cousin. I feel bad for them and I’m getting tired of her shutting people out with her “me me me” mentality. She even requested that her husband didn’t attend the shower because this is “her baby and she’s the mom.” She’s trying to learn to establish boundaries but it’s a hot mess.