Flakey group of women and my gender reveal

My mom , mother in law and best friend is supposed to be planing my gender reveal party Ive been so excited we have know for a while we will find out on the 7th of nov and don't won't to wait weeks after my appointment to find out the gender because their ill prepared, their all three flakey and not good with plans. My mom was an hour late for my wedding rehearsal, Taylor didn't even throw her own kid a 3rd birthday because of her schedule, and my mil is more of a follower than a leader so I'm extremely worried that it just won't happen . Three weeks away and not even a date or location has been talked about at all , call me crazy but I find it extremely rude to send invites to people when the event is less then a week away. They may have plans already and not have time to take off and have to miss something special because of no notice, do I push them to plan or do I just leave it be and not have one