
My main worry would be that it is to soon to have another puppy. I would not let you have one, without knowing you were an expert trainer and lived and breathed dogs with no other commitments.
You will have to take great care when allowing them to play as the older pup may not have the sense to hold back in his play, and too much could cause damage to the baby pup.
As they mature you may also find that they may compete, and in the meantime any training you have instilled in older pup may fly out the window and training the new one be much harder too.