My thoughts are . . . maybe you should think about adopting an older Yorkie, then you would be able to pick the one that best suits your wants. Their personalities can vary much like humans. Not all boys are headstrong and not all girls are headstrong. But if you look at adopting an older dog, you will be able to see their personality right off.
Besides, there are many older Yorkies that need homes and you can always get a 2nd Yorkie. Like a previous poster said, you can never have too many.