I have a 12 week old puppy that is so sweet to me and the people he is comfortable around, but he takes a long time to warm up to people. Whenever I take him to meet a new friend he isn't bothered by them until they try to pet him or pick him up. He starts barking and will even nip at them. I don't know if he is just shy and scared and this is normal or if i should be concerned he will be violent? I don't want him to have to warm up to every stranger that walks by when he is older....