Before they're 12 weeks old, a dog should meet a ton of people. This is really important from a developmental standpoint because dogs that don't socialize with others can become aggressive. It's just really important to let them meet other people and dogs. A lot of vets misunderstand the importance of this and they'll say, "Oh, you shouldn't take your dog outside until they've had every single shot," but that's ridiculous. If your dog gets sick, you're going to take them to the vet, and keeping them indoors for 4 months is going to be really damaging.