Had a female Beagle that didn't start until 6yo, had 3 litters, last one at 10yo.
First two litters went great. 6 and 8. Last litter had 6, but one stillborn and two faded. (I don't believe in tube feeding sporting dogs, survival of only the fit and strong seems to make sense to me.) So only 3 lived.
Mamma was healthy and strong the whole time, but I'd say 10yo for the Dam is too old.
Used to raise English bulldogs, and we'd stop those girls at about 6yo... but that was a ridiculous breed... don't get me started! They're a happening!
I think it has very largely to do with the health of the dog in question. But as was said, far more for the dam than the sire.
If I was in your situation, I'd find a great female and try for it, without question.