Welcome to YT! Congrats on your new baby. There are some very informative "stickies" around here. Since your baby is so young, it would be in your best interest to read all you can.
About the size, as everyone else mentioned it's really a guessing game. I like to look at the yorkie growth chart, but I realize it's not always accurate. I am just finding it fun to watch as my Lulu grows.
Also, I thought you might like to know that there is no such thing as a miniature or teacup...it's all just a marketing ploy to make more money. A yorkie is a yorkie no matter how big or small.
Enjoy your new little one!
