I don't think I'd look for Pregnancy advice on the technodrome

but here we are.
It's a personal thing, not everyone has the same circumstances, obviously your friend is going to be aware of the risks and considerations for starting later. Are you talking like late 30s to early 40's, which while we know carries risks, is still something we see or do you mean older than that? which isn't heard of so much.
I mean among those almost 40 to early 40s who are still fertile and in good health/good support etc there are those who feel it's still personally too old for them (considering the long term for example as well as the risks during pregnancy) and those, especially if they never had the chance to have a child before weight it all up and decide to do that. Of the people I know who were around 40+ they had planned sections for birth and were monitored more closely throughout.
Beyond gaining medical advice your friend is the one who knows her situation and can weigh up if it is right for her or not.