Question??

My first day of my last menstrual was July 4 2021, I had sex July 2 and July 26 2021 only. I am currently pregnant. It’s saying from my last Menstrual that I’m 8 weeks 2 days. Do you guys think that’s accurate because it seem like it’ll be 7 weeks. I don’t go to my first appt til Sept 13 when I’m “10 weeks”. What do you think? I’m anxious to take the Gender test but afraid it’ll be inaccurate because of my weeks