I thought a lot about chromosomal abnormalities and other age-related risks when ttc post 35.
I do think that if you are older it's important to think about it and to consider what you would do/how it would affect you, the baby, your family, but having said that, of course you hope that all will be well and the risks are not so high (imo) that the hope for a straightforward pregnancy and birth are unrealistic.
With ds1 (I was 34 when he was born), my background age related risk for T21 was 1:460 and after screening tests this went down to 1:20,000. I had no further testing and ds1 has no chromosomal abnormalities (that we know of, many of us do of course and live out our lives unaware of them).
No-one commented on my age when I was pg and I followed the same care pathway that a 24 year old would have.
With ds2 (I was 40 when he was born), my background age related risk for T21 was 1:85 and after screening tests this went up to 1:27. I had an amnio which carried a 1:150 risk of miscarriage, ds2 has no chromosomal abnormalities (see disclaimer above).
There was very little comment about my age, but I was put on a higher risk pathway which meant I got one extra scan and was officially under consultant lead care. In practice this meant seeing a registrar once in my pregnancy and ds2 was delivered safely by a midwife.
Like I said, it's important to think about risk, but also to think about your approach to risk, where your own cut-off is, what you feel is too high to risk, or too low to worry about, and that is different for everyone.