Pregnancy Dating Question


This may be a silly question, but for some reason it confused me lol. A few weeks ago when I went for my first ultrasound, I would have been 7 weeks 3 days based on my LMP. Ultrasound was dated at 7 weeks, so does this now mean that I go by the ultrasound dating since it adjusted my due date? Or do I still consider my progress as counted from the date of my last period? I'm guessing the answer is the ultrasound but just want to be sure. TIA 😊