My first draw for the Natera Panoramic genitive test I was 9w3d. I had no result but now I'm 12w3d and I just had it done yesterday.
Anyone can go for it so long as your willing to pay. I am 27 and was offered it from 10 weeks.
At 12 weeks, however I beleieve you have to be over 35yrs old.
You can go and get the 'harmony' bloodtest done from 10weeks. It's about $450 or so Though, but doesn't just check gender.