Is it rude to not show anyone sonograms of our baby until we reveal the gender? With my son my MIL…

Is it rude to not show anyone sonograms of our baby until we reveal the gender? With my son my MIL kept saying you don't have to reveal it I can already see it's a boy from the ultrasound picture. I know she really couldn't and it was a lucky guess, but it was just the fact that she was taking the fun away from it 👎🏻