You can find other threads with this topic. I strongly suggest you wait until your puppy is 6 months old. Do it as soon as he turnes 6 monthes. Getting the dog neutered, even at three months, is not going to stunt his growth or make him less protective of your or your home. The reason I say wait until 6 months is the puppy can withstand the anesthetic a lot better. I honesty would be worried if your vet wants to neuter your puppy at this age. I would call arund and ask other vets what their opinions are on this matter. Not all vets are created equal!

Good luck with your puppy!