I hope you can understand this,
Kittens are young cats that are raised alone with their mother if feral, the father plays no part in rearing the young, he only gets the femle pregnent. A female cat can have babies from more then one father too and she can get preg again only a few days after giving birth. when Bast ( a pagan goddess) was said by the early egyptians as a goddess of fertality they were not lying
By the time they are 16 weeks old they are out on their own, A female will have as many as three litters a year which drains her strength, she can get cancer from her heat cycles, the males live even worse they start spraying and roaming around in search of females in heat, they devlop pads on the sides of their faces and spines on the penis, (these changes can be prevented by neutering)
Few feral cats ever reach double digets, they live lives that are too dangerous.
On the other hand kittens that are raised indoors or allowed outside on leashes while being closely supervised can be expected to live 14 years or more, sense they get spayed or neutered and have all their shots and reg vet checks. Do not allow cats outdoors without supervision, fed a good food thats high in met content or make a raw/barf diet an option. Get a good litterbox and fill it at lest four inches deep with litter. Pm me if you want more info.