I can only say " God Bless You"
Based on the data you have provided , There is no way of telling 100% , whether you will have a Trisomy21 baby or not.
But the way you are worried at the hypothetical consequences, I can tell you , your baby may have other problems like IUGR etc. Worry in a
Pregnant Lady will cause problems for Fetus in womb.
So Stop Worrying and Start Enjoying Your Pregnancy.
Your Obstetrician will take care of those problems. What you can do (good ) for your baby is- Eat Well , Be Happy and follow your Obstetrician.