Gestational sac & yolk sac size @ week6

I did an abdominal ultrasound at 6w, and CRL was about 0.33cm! But not too sure how accurate it is cos it was so early…. At my 8w scan, CRL increased to 1.52cm!

maybe week 6 is too early? not sure though but I rmb I had my first scan on the 8th week