Your pup should be spayed and/or neutered around 5 to 6 months. Your vet will let you know when the appropriate age is. I do not believe in pediatric spay and neuter. I do understand why some rescues have begun doing this, however, it can create urinary tract problems later in life.
Unless you are going to show your dog in AKC, PLEASE, PLEASE, PLEASE spay or neuter them. There are so many unwanted animals in shelters being euthanized every day. Do not add to this problem. Additionally, an un-neutered male will be more likely to mark, take off to find a female and fight another male. If you neuter a male too late, you also may not be able to do away with unwanted behavior, such as the marking.
Did you know that there are over 70,000 puppies and kittens born in the US every single day? That's 7 times the number of human babies born a day