Gender wrong on panorama test?

Okay I don't know if this is a ridiculous question.. but I just read somewhere that if you had a boy recently there could still the the Y chromosome in your blood stream and could show up on the panorama blood test? I just got my results the other day and they are saying a healthy boy but I also have had 2 boys in the past 2 years.. the only reason why I'm curious about this because I was convinced this had to be a girl because this pregnancy is completely different then my first 2 with my boys.. what does everyone think? I was very happy to hear we're having a healthy baby boy but when I read that it made me question if I should hold off on my shopping until 20 week scan 🤦🏻‍♀️😬 lol