In which week did you find out the gender ?

Hello ladies!!! Those who are finding out the gender. In which week did you find out and was that a 2D or 3D ultrasound or blood test? I am in china  and here it's illegal to find out the gender but if you are a foreigner they can tell that but I have to pay for it. Insurance won't cover it. So I was wondering when to book an appointment. And I have to go to a private lab.