try not to stress hun, ive been where you are, i was 26, my scan was perfect, but bloods were bad i had 1/82 chance of downs.
The best thing is that the scan was good and all indicators were good as in nasal bone, nt measurement, only being from your bloods is a good thing, and thats why your dr is telling you not to stress.
There is lots to consider here, and it is a very personal choice, and for individual reasons. For us we wanted to be prepared so went ahead with the amnio.
You do not have to go ahead with an amnio, it is your choice, no one should have booked you in without your consent and you can cancel it if you are not comfortable with having it. It does carry a risk of miscarriage around 1/200, and for me it was a painful procedure, and when i left i had contractions for hours after (nothing too bad but at 15weeks stressfull none the less).
However it will tell you what you want to know, if you want to know. It is quick and simple.
My advice is to go with someone who does them all the time, the more experience the better, and ask for the fish results, which means for a fee ($175 back in 2009) you can get results for the main concerns within 48hrs, often sooner, i got mine in about 20hrs. Then the full results, for all conditions that are tested for come back to you 2-3 weeks later.


I was cleared for downs, then told the bloods could also mean a heart defect, which was cleared at 20weeks, and placenta issues which i had to wait till 32weeks to get the all clear for.
They get it wrong far too often.

Goodluck, just remember if you dont feel comfortable, this procedure is not mandatory.