US - Accurate?

So I have my US on Friday which will allow me to find out my baby's gender and a whole load of other things. I'm 16 weeks and 2 days pregnant but on Friday I'll be 16 weeks 6 days, do you think it'll be accurate? They say you have to be over 16 weeks to find out but I'm just curious what you ladies think.... what did your scans look like?!