What week was your first ultrasound?

What week was your first ultrasound? I found out we were pregnant on 12/3 and our first ultrasound was at 6 weeks on 12/23. There was a sac but no embryo inside.

I have been doing a lot of research and asking around and have been told 6 weeks is very early for the first ultrasound. Looking for help to ease my mind!

Thank you all and merry Christmas!