[_Mochi_]

Hello, this is my first post and I'm new to this forum.
I have a 5 months old yorkie mix. I got her when she was 4 weeks old from a coworker of my cousin's friend (if that makes sense lol). I didn't know what she was because I didn't see her parents and I heard both of them were mutts as well. Because I didn't have much knowledge about dog breeds, when I saw that she was all black and with a light/tan chest, paws, and 2 dots on top of her eyes like eyebrows, I thought she would look like a Chihuahua mix or something. By 3 months, I was shocked because she looked like a yorkie e-e. Her flobby ears stood up and her fur changed and she started to grow white/gray on her head and body.

And now at 5 months, surprisingly she has a silk coat and her silver root has grown more than 1 inch; however, her baby coat got super dry and would get tangled, and she looks like a grandma. So when I should shave her?