Does anyone have a child with Down syndrome?

My baby might have downs they want me to do the nipt that I decided against and they also want to do another ultrasound at 32 weeks I’m 30 weeks now. When did you find out your baby has downs or did you not know until birth? Could you see any signs on ultrasound like facial features being different. I’m just trying to process this because they told me I had nothing to worry about at my 20 week now they’re freaking me out again 😭 obviously they must know something if they want me to do another ultrasound and testing.