When I was expecting DD in 1980 I was offered an ultrasound to check my due date, Hospital was trialing a scanner, I was asked if I wanted to know sex of my baby, no I opted to wait.
DD wanted to know sex of baby with DGC2, she & her OH payed for a private scan as NHS one wasn't clear enough. Only reason she wanted to know was they already had DGS1, small 2 bedroom house, turned out to be another boy. DGS1 had gone with them, he was so excited he rang me as soon as they got back to the car.
DD's best friend organised a "baby shower" for DGS2, DD didn't really want it but went along with it, I was away & missed it that was good planning
I hate the idea of reveal partys, why would you let some-one else know first