Ultrasound for Gender

I’m 15 weeks and 5 days. I finally went for my first ultrasound yesterday and while I was there we try to figure out the gender! When baby didn’t want to show us due to the way the baby was positioned and the baby wouldn’t budge. I really want to know as soon as possible but I don’t know if I should schedule another ultrasound or should I wait to my next appointment in 4 weeks? Needing some advice