Shy baby??

Je
Anyone else been 3 times to get the baby's gender and the baby not show? This last time I wasn't even supposed to get a ultrasound and my dr agreed to try again and still didn't show. Dr said the baby's legs are already cramped in there that there's not a good way to even try to get a gender at this time. But says once my uterus expands should give the baby more room to move around. My next scan is at 23 weeks just wondering if anyone has been threw this and went back after 20 weeks and find out the gender? We really want to know the gender so we can get things ready but it's already been 5 months almost I think if we go back and the baby doesn't reveal we are just going to wait till delivery.