questions about early U/S

Liz
How accurate are untra sounds for the gender reveal at 17 weeks? 
My husband wants to take off and go to the ultra sound with me and then make a fun day if it by taking out two little ines to the zoo after. I'll be 16 weeks tomorrow so 17 weeks if they can get me in would be great if it's accurate! If not I'll have to wait until May 30th😭 that's so far it's seems like! Haha being drama. But only May 2nd and May 30th work great around our schedule..