What is the earliest you can get an ultrasound done to find out gender? I can’t get the blood test done without paying like 80-90 out of pocket...

I’m going to ask my OB next week to see if one can be done 16/17 weeks I want to surprise my bf for his birthday next month before Christmas..since he hasn’t been able to come the appointments on top of it he broke his ankle 😣 and hates he can’t help me as much as he would like to. He’s hoping for a boy of course but either way he would be happy. Please let me know if you personally have been able to get one and it be accurate before 18-22 weeks??