its still too early. my yorkie is 6 months old and only her head has changed colour. it can take up to nearly 2 years for their hair colour to change completely, it all depends on the dog!! although i'm starting to see some dark grey coming through my yorkies body, so she may not go very blue in colour :)
Yeah, my little guy just turned 16 weeks today and his hair on his face is also turning. His parents were both blue and tan, so this kinda lets me know that you never know what they will look like when they mature.