As long as you are knowledgeable in the breed and with training, you should be fine. Also be aware of any past history the dog has, where it came from, etc. This will help better your knowledge as to whether or not THIS dog is right for you.
The breed has many faults, but their history is of dog aggression, never people aggression. They were never breed to attack people, but other dogs. Keep this in mind.
Also, keep in mind that the breed was once known as a nanny dog breed, keeping watch over the families' children. Some of the fighting dogs, that made it to retirement were even rewarded with family life as just a pet.
It's not the age of the dog that should be the concern. The concern should be your knowledge of training and the breed. The concern should be the individual dog in question. The concern is you and your household.