Welcome to YorkieTalk! Your little ones are precious. Although I love 'em all, there are specifics regarding the conformation/weight of Yorkies. AKC is generally recognized as the leading registry of purebred dogs and according to AKC yorkies are to weigh no more than 7 pounds.
That does NOT mean that yorkies weighing over 7 lbs. are not purebred - it simply means that they do not meet the standard set forth by AKC for conformation shows. You would be surprised (or not) to learn just how many 6.9 lb. yorkies
that are successful on the show circuit.
It is hard to accurately chart adult yorkie weight unless you know the genetics behind the dogs, however once a yorkie reaches around 6 months of age, their growth rate generally slows - not always, but generally. There are many sites you can go to that provide yorkie growth charting - but remember this are only guidelines. If you Google Yorkie Growth Chart you will be bombarded with hits.
With all of that said, your sweet baby girl is basically 20 weeks and at 2.9 lbs. (2 lbs. 14.4 oz) she is charting just under 4 lbs.