MIL issues

My mother in law and I are actually really close. I'm closer to her than I am my own mother. But lately she is so excited that I'm expecting that she tells EVERYONE, which would be ok, if she let me make my own announcement first. She feels like she gets first dibs on telling everyone. She even tried to announce it on social media before me. And when I asked her to take it off she flipped out and hasn't spoken to me since. Any advice on how to handle this? I know she is just excited, but I feel like she is trying to steal the spotlight from me and my hubby.