Is it rude to uninvite children at my wedding?

a difference between uninvite and not invite. Send invitations with the adults name on them. Let everyone know that you are not inviting any children. If they cant get a sitter, then they have to stay home. If someone shows up, have them turned away. Appoint a person, like maybe an uncle to do that. don't let them spoil the wedding. If they are rude enough to bring the child uninivted it will probably make a big problem and other folks who got sitters will resent it.