Gestational age or baby measurements?

Rebecca

I did <a href="https://glowing.com/glow-fertility-program">IVF</a> so I know exactly how far along I am. Yesterday at 11w4d I had my NT Scan with a maternal fetal specialist and he said baby is measuring 12w2d and that from now on in the pregnancy we will go off of that. I understand doing that for natural conception as the ovulation date is somewhat unknown, but with <a href="https://glowing.com/glow-fertility-program">IVF</a> we know exactly what day. Just seems strange. I know it’s only a few days different but I’m confused! Did anyone else experience this?