Hi,
Welcome to YT!
I don't think that is a big for a yorkie at all...I'd say she'll probably be within the standard, under 7 pounds. There is a growth chart some people use to help estimate their full grown size. You take their 12 week weight and double it and that is supposed to be their full grown weight. There are always devaitions though and it isn't always accurate. Some quit growing a lot sooner than others do. My little girl is 1 pound 11 ounces at 16 weeks but she is very small. She was 1 pound 9 ounces at 12 week, She was estimated to be around 3 pounds but I don't know if she will get to be three pounds or not. I am keeping my fingers crossed and hoping that she will
My little girl eats all the time though. She is the biggest pig! So long as you are feeding a good quality dog food don't worry about how much dry food she eats. She is a puppy and needs those nutrients to make her a healthy girl! Feeding her less won't make her smaller, just more sickly . My little girl eats about 1/2 cup of Canidea All Life stages daily if that helps you at all.
If you have any more questions or need anymore help feel free to PM me anytime!