Want to know how old your dog is in human years? It's actually not as simple as multiplying by seven.
Dog years vary a lot, based on breed. For example, a German Shepherd will live about 10 years in total, but its lifespan is comparable to that of a human who is 70 years old—meaning it's considered middle-aged. A toy poodle can live to be over 15 years old—about the same age as a 100-year-old person.
The reason for this discrepancy has to do with how quickly dogs grow up: they reach adulthood at six months, whereas humans take 20 or so years. A puppy that's 12 months old already has most of his adult teeth and will pass through puberty faster than you could say "woof."
So while it may seem like he's aging extremely fast, he's actually just going through all the stages of life much more quickly than you are—and he'll have plenty of time left over for naps, snuggles, and treats!