Gender

I had my ultrasound yesterday and we had the nurse write down what the sex was and put it in an envelope because we're having a reveal party Sunday and we didn't want to know until Sunday. So when it came to the tech going to look at the sex she turned the screen and said I think I already have a good idea what it could be and it took her like 30 secs And she was like yep I got it!! Could it possibly be a boy? I feel like when it's a girl you really have to look not just already have an idea. Anyone...