My Jilly went downhill in 9 weeks of having another puppy around, stopped eating, lost weight, shed, chewed her ankles and generally stopped living while the pup was around but she was a special-needs dog all her life & I should have known better than to try it.
Most grown dogs are a little put off by puppies and slow to accept them but given a few weeks of the little charmers and the pack nature of dogs, they slowly grow to accept and love them dearly, will defend them with their life. Go slowly, don't expect miracles since your dog has been your one & only "love" all this time and is probably pretty jealous at first, too. Just give your dog time to adjust, bathe her with love & affection, don't force anything at all, let her accept pup in her time and her ways and let them work out who is going to be the pack/family leader of the two.
My Tibbe is a gregarious little social hound and he would dearly love a pup like this in his life, accept it readily & happily from the moment its feet hit the floor! But most dogs are not Jilly or Tibbe and take a little while to make the huge adjustment from "only" to pack.
__________________  Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |