I am the parent of child with D/S. He was my first at age 25.
Only ways to test specific for D/S is
CVS, but it must be done early and you may be past the time frame, and
Amnio, done in a much more pregnant state. Risks of miscarriage are not much different (CVS probably higher because done in early stages when most miscarriages occur anyway). CVS can be done two ways, amnio one way. CVS can not detect spina bifida, Amnio can. I had two CVS tests with next two children, one each way.
All screenings and blood tests are just that, screenings. They are not proof that a baby is healthy or not. If you are concerned and want answers, these tests should not be relied on. These screenings are an important tool for doctors/malpractice issues. If tests are wrong, they offered you all they had. You refuse the test, your choice. They are covered.
If you have decided you would carry the baby to term and feel you can continue without knowing one way or another, then I would not have the test.
If you want to rule out any issues, or plan & prepare your next step afterwards should some be found, then I would have the test.
Good luck with all and congrats
