Your pup looks adorable! Silky coats usually start with pup having thin hair on the top of the head. Some worry they see scalp, some say the roots are silver, or just that it is too thin. That is a good sign -- will probably result in a nice silky coat.
Wait til the 5-7 months stage -- very unruly hair and often look unkempt and not the yorkie-look we are waiting for.
I used to have those "awkward days" pics in my avatar. I kept them there for a long time, and used them as an example that yorkies do go through some big changes along the way to becoming the most beautiful dog in the world.