When would be a good time to announce baby's gender?

I'm beyond excited to finally have a girl after having my boys but when would be a good time to announce? I found out through blood work and I'm only 12 weeks. I'm scared that would be too early to tell people and I'm also scared that they may have messed something up or we did the test too early and I'm actually having a boy. Hubby says I'm overly paranoid but I'm just so scared to get my hopes up. The grandparents already know but I want to announce to the world how excited we are lol. What do you ladies think?