It depends on the kid. I got my first dog when I was twelve or so, after years of begging.
Now, I was a reading kid. I loved to read. So when my folks wouldn't get a dog when I first asked, I went to the library and read every book on dog training and dog care they had, as well as memorizing all the AKC breeds and a few extra breeds (not on purpose, but one of the books had illustrations of all of them.)
At the point where I was leaning out the car window excitedly shouting, "Look, a bichon frise!", my parents decided I was serious about this dog thing and we went to the animal shelter.
I don't regret them making me wait, though, because I learned so much about dogs from those books, including why pet shops are bad and why backyard breeders should be avoided. I think a good way to see if a kid is "ready" is to insist that they "go through the motions" of feeding and walking the "dog" before you actually get the dog . . . Like if you intend to get a medium breed that needs to be walked an hour, the kid has to walk for an hour every day at the same time as he'd walk the dog. If they do that for six months, they're more likely to actually do it when the real dog arrives. Although parents should always be prepared to step in if the kid doesn't live up to his responsibilities, for the dog's sake.
Now, I was a reading kid. I loved to read. So when my folks wouldn't get a dog when I first asked, I went to the library and read every book on dog training and dog care they had, as well as memorizing all the AKC breeds and a few extra breeds (not on purpose, but one of the books had illustrations of all of them.)
At the point where I was leaning out the car window excitedly shouting, "Look, a bichon frise!", my parents decided I was serious about this dog thing and we went to the animal shelter.
I don't regret them making me wait, though, because I learned so much about dogs from those books, including why pet shops are bad and why backyard breeders should be avoided. I think a good way to see if a kid is "ready" is to insist that they "go through the motions" of feeding and walking the "dog" before you actually get the dog . . . Like if you intend to get a medium breed that needs to be walked an hour, the kid has to walk for an hour every day at the same time as he'd walk the dog. If they do that for six months, they're more likely to actually do it when the real dog arrives. Although parents should always be prepared to step in if the kid doesn't live up to his responsibilities, for the dog's sake.