help!!

So we originally had our "big" ultrasound scheduled for 12/14 and we invited some family over on 12/16 to have a gender reveal Christmas party. Well now I had to have my ultrasound moved up to this Friday and I know I will not be able to wait that long without finding out for myself! I am struggling now whether to cancel the party all together or still have it and just reveal to everyone else? This is our third baby and we've never done a gender reveal party. Help please!