Gender Reveal Help

My first baby is on the way! My husband and I already know the gender of our baby but also want to have a gender reveal party for our family and friends. I’m kinda confused...I’ve only ever seen gender reveals where the parents don’t know the gender yet. Is it ok to have a party if we already know? We just couldn’t wait to find out, but this is our first child and we really want to celebrate an exciting moment with everyone too. Should we just act surprised? Will people be disappointed if we tell them we already know?