Proactively socialising your puppy is very important. Puppies have what is called a ‘critical socialisation period’ between approximately 3 -17 weeks of age. The puppy’s experiences during this critical period of learning and development can influence and shape their behaviour well into adulthood. Providing plenty of opportunities for socialisation and exposure to different environments during this time can help to ensure your puppy grows into a well-adjusted adult that relates well to other dogs, other animals and people.
Socialising a pup must be done in a safe, social and positive environment such as that generally provided at a puppy school. Puppy school is generally aimed at pups between 11-18 weeks of age. This is to try to coincide puppy school with the puppy critical socialization period whilst also ensuring that the pups are sufficiently vaccinated prior to being exposed to other puppies.
You can also take your puppy to meet with the puppies and dogs of your friends and family, either at your house or their house. But you should make sure that the other dogs and puppies are friendly, healthy and up-to-date with their vaccinations.
Your vet will be able let you know when it is okay to take your puppy to other environments such as the dog park.