Ultrasound to find out sex!

I'm 14 weeks today but I have an ultrasound scheduled for July 2nd to find out the sex. I will be 15 weeks and 3 days when I have it done. How many of you found out that early and was it accurate? I know they say that waiting between 18-20 weeks provides the most accuracy but the place I'm going to said that they have never been wrong and honestly I'm so impatient I can't wait until 20 weeks!