Has anyone ever been told you were having boy/girl and the tech was wrong?

[MrsGax]

Hello! So I am still early, but I wanted to find out the gender at one of these places by my house that supposedly can detect the gender with 99% accuracy after 13 weeks... My question is, has anyone ever been told they were having a specific sex and then found out later that it was wrong? I just do not want to find out and then be told something else cause I feel like that would make things weird. I thought of finding out at like 14 weeks... but then saying that it could be the other way and having the dr tell me at 20-22 weeks just to not get set on a boy or a girl. I am just wondering how often they get these things wrong. Thank you!