When to tell family

My husband and I were ttc for 26 months before we finally got our bfp. Neither of our families knew we were trying. They actually think we dont want kids and we've been holding out on telling them for this extra special surprise. My dad passed away this past December and it kills me knowing hes not here for us to share the news with him. I'll be 7 weeks on Saturday and my dads birthday is on Sunday. Our first one since he's gone to Heaven. My mom sisters and nieces and nephews are still getting together to celebrate and I thought it would be perfect timing to announce to them that day. I think it would just be even that much more special. We had an ultrasound today and got to see and hear the heartbeat. My husband is now worried it's too soon to tell family. Any advice? How far along were you before telling parents and siblings?