The people who are skeptical that Luma is a yorkie probably don't know much about yorkies or what they should look like when they are pups.
Luma is a darling girl.
Maximo looked like a funny little muppet until he was about 10-11 months old. I loved the look.
Hair growth depends on the yorkie and breeding lines, and quality of coat. Cotton coats tend to grow really fast, but some yorkies with gorgeous silk can produce a full coat by one year.
As KJC said, be patient. Enjoy the funny, "awkward," stage.