Kid free church ceremony - is that right to do?

Nope, shut her down and keep what you've said. My MIL tried to start crap with my FH and make him feel terrible about the possibility of us not having his sister's kids in our wedding (we wanted them there and they will be, we just didn't have everything figured out at the time and wasn't sure if we should have kids in the wedding party if we weren't allowing any others) and because of that she's now kicked out of knowing wedding details until after stuff is finalized.

If they're annoyed then they're annoyed. I'm sure it's harder to find a way to get your kid somewhere else between a ceremony and reception than it is to find a babysitter for the whole time, so if they won't come because the kids can't come at all then they probably wouldn't come if they can't go to just the reception. I'd refuse to talk to her about this anymore and make sure your MIL knows kids won't be invited in case your mom tries to rope her into her plan.

I've dealt with the same thing but my mom's the one who has been super chill while my MIL has been such a pain lol!

Like I understand that church is a public place and technically anyone could come watch your ceremony if they wanted to, those people aren't usually going to be connected to your guests. Once someone who is connected comes then they're automatically going to feel like they should get to go to the reception too. And while the kids themselves won't care, their parents will. Why get your little ones dressed up for church when they can't go to the fun party after?

If you don't want them there, don't agree to it. Her logic is way off anyway, and she's just trying to railroad you into it. Keep telling her No (if that's what you and your FH really want), your decision is final, and that you will no longer engage in conversation on that particular topic.

Like the others have said, don't agree to it and stand your ground. You're not in the wrong and if you don't want children at your ceremony, you don't have to have them there!

I'm not religious, but as far as I am concerned even if a place of worship is a public place, private events can still happen at a public place. So if a private event is happening at a church only invited guests are welcome to attend at that time.

It's 100% okay to want a kids free day, and I do not think you should feel forced to make any exceptions to that rule if you do not want to. You can have a kids free ceremony as well as a kids free reception.

Do whatever makes YOU happy! If you want a child free day, I suggest having it! While you cannot ban people from bringing their children to church, most guests will respect your choice (I say most because there are always a few). My SIL wants to bring her children and FH and I have been firm and stood our ground. She has asked about 11 days so far, and our answer has remained the same.

1. While we love your little ones, we have decided to have a ceremony and recption for (21+ or whatever it may be). Unfortunately, if we make and exception for one person/family, we will have to make it for others

2. Also, you can use Covid as n excuse, saying you would prefer to keep the guest count lower, especially with restrictions changing all the time.

3. to appease Mom, you can always have the niece in the room with you while you get your hair and makeup done.

Good luck!

You definitely have every right to have a kid free ceremony an reception, I don't think you are wrong at all!