As has already been stated, there are risks to having children after 35. It is also sometimes harder to become pregnant after age forty. So, I am not going to get into that, but I had my first child at 26, my second at 27, and my third child three days short of a month after my 40th birthday. All three of my pregnancies were relatively easy, all three of my deliveries were natural, and all three of my children were born healthy, smart, and with no chromosomal abnormalities.
That said however, there are some differences, both good and bad, about parenting after age forty that no one is talking about.
Parenting a new child when I was in my late twenties and early thirties (or in my case, two new children), I had a more abundant supply of energy, and was able to run around with them more when they were toddlers, but I was also, as a new mother, more uptight about little things that I now know to be silly or unimportant. In my twenties, my husband and I were newlyweds, and struggling to make our place in the world, in our forties, we are more relaxed, and financially stable, so it is easier to provide for our youngest, than it was for our two older children. I find that I have much more patience with our youngest than I had when our two older children were small.
Whatever age you are, I think that all babies, no matter how they arrive are a blessing. We had tried to have a third child before I turned 35, and it just never happened so we didn't plan our last child, she was a surprise gift that we weren't really expecting, but I wouldn't trade her for anything, she has brought unimaginable joy, (and a few challenges) to our lives.
My younger sister, also didn't marry until late, didn't get pregnant until she was forty, and had a perfectly healthy beautiful boy last July, she had just turned forty-one. I would tell your daughter to consult her physician, have all the tests, and if the doctor says she is healthy, and she and her husband want to have a child, they should absolutely go for it!