Are we in the wrong?

My husband and I decided to share yesterday night around 8 PM our baby shower save the date invitations. We sent it to friends and family and posted on social media. His sister is now pissed at us saying we tried to steal her limelight because earlier that day around 10 AM she posted on social media that she’d found her wedding dress. We were excited for her. We weren’t trying to steal anyones limelight and honestly the only reason we made the announcement is because my husband has family out of town that need to make travel arrangements by June which is when the baby shower is. The sisters wedding is later this year in the fall. I will apologize to her if I hurt her feelings or stepped on her toes, but I want to know if that is even necessary. It all seems pretty trivial to me but I definitely don’t want to hurt anyones feelings or stir up drama. Are we in the wrong?