Boy? (18w)

My ObGyn didn't do the anatomy scan during my visit on Friday. He said I have to wait 4 more weeks when I'm 22w so my husband and I paid for an elective ultrasound the next day. Our baby wouldn't cooperate but the tech was so patient and after almost an hour told us it was a boy and she was certain it was. We're excited because I was hoping for a boy but I've heard stories of techs getting the gender wrong. What do you think? Is it really a boy? This is our first baby.