I feel for you, I have the same thoughts and my dog is 5 years old. I can't imagine how devastated I'll be when she's gone, but I couldn't stand the gap between her death and buying another puppy. I think getting another puppy now is a good decision - your dog will educate the new pup to some degree, and that's important. Cesar Milan did the same thing, he even let his old pitbull pick the next puppy.