J.
I just wanted to add to something someone else posted - CVS, if done by someone experienced who has had good results, is considered to be as safe as amnio. Check with your own OB, of course, for the actual statistics.
You can also look into the non-invasive screening including nuchal fold measurement. I did that with my second pregnancy since I was over 35.
Personally, I think I would want to have whatever information is available as early as possible no matter what. I have a friend who has a child who has Down, and there is a lot of education you will need to have, services to sign up for, etc., if you are thinking of continuing the pregnancy.