I can't tell you not to worry because of course you will and that worry doesn't go away even when your results are fine and it gets worse after bub is born. We are always worrying about something.
But in saying that I would say the chance bub doesn't have trisomy 21 are great. Your age alone will put you at a much greater risk or having a baby with a trisomy so that will increase your risk on its own despite the blood test and NT measurement.
I would continue with the CVS as you said you have planned however although 1:4 is high such a large amount of women have high risks and results such as your's turns out to be a false alarm.
Thinking of you and hoping your results for the CVS are speedy so you can then continue to enjoy your pregnancy without the worry.