I have to agree with Carrie that you are already showing signs that this dog will be uncontrollable in a few short months. He may be okay with you but is he okay around other people? Do you want to take the chance? There are professionals who can help you train this dog at this point but if you wait to much longer you may lose the edge (or the willingness of anyone who can help). I would never tolorate my dog growling at anyone for any reason. You need to be the ALPHA in the house and take control of the dogs behavior problems with either a specialist training the dog and/or you

It is a task worth taking for the love your dog will show in return Best of Luck