Ultrasound at 6 weeks or 8 ?

I had an ectopic pregnancy and then a miscarriage and then a missed miscarriage just 2 months ago and I’m now pregnant again. My doctor did beta hcg testing and it doubled and he said he’ll see me when I’m 8 weeks for my ultrasound. I feel like it should be at 6 weeks due to my history and I have alot of anxiety over this. Should I ask for a 6 week ultrasound or leave it ?