Gender Appointment Help!

Em
I'm from North Carolina and my SO is from Missouri. I'm 12 weeks and 1 day today. He wants to travel home from July 18th to July 28th, during this time I'll turn 15 weeks. I have an appointment on August 5th to find out the gender. The problem is that we haven't had one appointment to ourselves. He's only been to one and I had another family member go. For my gender appointment, we're having a few family members go. I thought about getting a private 3D/4D ultrasound while in Missouri with just us. I feel like it's such an intimate thing and we want the chance to do it alone but we don't want to hurt anyone's feelings. The appointment would be for the 19th. Should we go ahead and have the private session in Missouri or wait and come back with all family? Or have the session privately, keep it a secret, and keep the appointment for August 5th for the family to go to?