
It is normally recomended to have a good age gap between two dogs. It allows you to have the first well trained and well behaved, so that you then can concentrate more on a new puppy. This is the reason most breeders never sell teo pups together as it can cause more probelems thatn the average person can cope with or anticipate.
You could have hierachy probelms, problem of over bondi9ng by the dogs to the exclucion of yourself, twice the damage to your yhome wityh teo naughty pups egging each other on. Also the older pup with it's lack of amaturity could inadvertently hurt the new one.
Why not think of an Adult well mannered rescue of up to middle age, who would be company, and a role model for the puppy? Or alternatively wait another 18 months or so to get another pup. :D