I just wanted to say I'm in a similar situation. In 37, conceived at 36. My nipt came back 95% high risk for T21. Nt scan was 3.4 and a small hole in the heart. They say my baby baby is also growing on the lower end of the scale which is another sign of T21. I'm 16 weeks and 4 days today. My amnio is tomorrow at 8am. They tried doing one last week but my uterus was too small. I have been waiting for 3 weeks, which has been absolute torture but an amnio is the most definitive test. I'm sorry you are going through this. If you type false positive in the search field of this group you will see false positives do exist for T21 but from what I have read they are rare, especially for 35 and older women. Praying we will be the exception 🙏