I was only 32 when I got pg for the second time - yes, you are in a "high-risk" category if you're over 35, but it's probably not nearly as high as you think. There are certainly plenty of mums on here who have had children after 35 without any problems.
As I said, I had an amnio this time round too, even though there were no other factors (eg. AFP results) that indicated I should. I was almost able to deny to myself that I was pregnant, and it was a bit like finding out I was pg at 17 weeks when I got the results, and the rest of the pregnancy seemed to go very quickly. We got a scan at 12 weeks - usually at about 16 weeks now in our hospital - and as everything seemed fine, we opted to wait until 16 weeks to have a less risky amnio rather than CVS. At least nowadays you get the results of an amnio very quickly. Once I'd got the favourable result, I didn't actually worry too much - looking back, I realise I was more concerned about an undiagnosed breech presentation!
On the subject of trying again: I think my periods returned quite quickly, and as we've not had any problems conceiving, I more or less chose when I wanted to have another baby. Personally, I don't think any time is "too soon". There's no doubt that being pregnant again & having my son have helped me get over the loss of my second child.
It is hard to come to terms with the fact that you've chosen to end the life of your own child - there are days when I can hardly believe I did such a terrible thing. I'm still convinced I did the right thing though, and that makes things easier to accept. I'm glad you're getting the support you need from those around you.