Go get a private 3d ultrasound.
Baby can change position at anytime. Lucky my baby changed position when I found out at 34 weeks. But now it's head down. It really depends on the position of the baby. I'm 39 weeks nw. They say baby girls make you gain more week and look bigger while boys tend to make you look more slimmer
Unfortunately unless I'm late or something is wrong I won't get another ultrasound. So he or she will be a surprise. We already have a beautiful son so we would love a girl but I'll be happy either way.
3D actually doesn't show gender any better than 2D but some places you can purchase a 2D as well. Me and my boyfriend actually have gone twice to a place to get the gender early. It was $99 for a 2D and like $220 for a 3D! Just look around if you are really eagar, theres tons of private places (: