Gender ultrasound question

I see a lot of people posting they are having boys at 12-13 weeks. Our tech at our gender ultrasound told us that it's not possible to determine at that stage because both have a nub and look too similar from the between the legs shot. We found out through a pelvic bone which develops differently in males and females. I also read so many people saying they were told that early and then baby turned out to be a girl. It's just making me nervous for all you all finding out that way this early. Did your techs seem confidant? Mine was and said he's never been wrong but we also didn't look for boy or girl parts.