For Golden Retrievers, the females tend to be a little more independent and the males are a little more 'velcro' - the kind that follow you from room to room. You can't go wrong with either.
Good breeders often have waiting lists, so don't wait too long before you start making some calls and visiting some breeder's homes. Trust your gut - there are a lot of bad breeders out there so if you get a bad vibe - get out of there!
Many try not to have puppies available around Christmas. They often think the holidays are already too chaotic and worry about the puppies in their new homes or the fear that people will give their puppies as gifts. If you can't get the puppy for Christmas for your kid, you could wrap up a bunch of puppy toys and supplies or puppy training books as a gift instead so they know one is coming.
Good luck in your search!