6 lbs at 14 weeks? oh boy!!!!!!
my dog's half sister casey was the tiniest puppy when she first came home. actually she was smaller than mickey. half of him when she first came home. however, she's now close to 20 lbs while mickey is lingering around 9lbs.
so it is possible to have a yorkie larger than the typical 7lbs.
as long as your puppy's healthy, thats all it matters