Doctor wont give an ultrasound until 20 weeks.

I went to my first doctors visit today. Im 15 weeks exactly. She refused me an ultrasound until 20-22 weeks. The paper says 16 weeks. But she said she wants blood work done, that i already had a month ago and gave her the records for it. Ugh. I'll be 17 weeks next appointment and she said no ultrasound that appointment but the one after that. I know i have to wait but i mean, come on. Everyone else there got there's early and got to see their baby. I really wanted to know the gender as soon as possible because my hubby only gets calls once every 2-3 weeks and the day he calls would be the day i could have gotten one and i maybe could have told him the gender. So we would kinda be finding out together