Just spotted this thread and was wanting to see how things are going...
I have two cousins with Downs, and my best friends son, as well... LOVE them all...they are the most joyful children....it really isn't the worst thing in the world. I remember when Vanessa was born, the grandmother told me I was the first person that simply said CONGRATULATIONS...
But, that being said, these tests are notorious for inaccuracies, and I would tell your daughter to BREATHE deeply and not get too worried...
Good luck, and keep us posted!