My girl is a little over 10 months and will be 11 months near the end of this month. She's last weighed at 11.2 lbs, but even the vet and I agree that she's a little bit of a chunky monkey (she was fed alot X_x). Since she's got LP, she's needing to lose just a couple more pounds so her perfect weight should be around 8-9 lbs. I'm noticing she's been firming up more and has a little loose skin, so I'm guessing it could have more to do with muscle weight as well, but I still feel a good layer of fat on her ribs. She's also pretty tall and long bodied, but she's dainty framed and structured. Her mom was around 8lbs and her dad at 5lbs (saw them both, the momma was a little weary of me and the daddy was a little spitfire). So it's like she's got her dad's daintiness and her mom's size and length X.x lol I wouldn't call her frame large, just long (as a human, she'd be tall and slender). She's also been fixed once she was a little over 6 months old and the vet said that she might grow a little bit longer framed because of that, but it varies for each dog (also doesn't help it made her gain weight easier
). On one hand, I'm glad she didn't turn out to be a tiny dog, I'd be stressing over her more. I've debated at one point of getting her hormonal therapy after being spayed, but the vet assured me that even if she does grow longer framed than her original normal self would have, it wouldn't be by too much terribly much. So far she seems to be stabilizing in her frame and is starting to fill out more. I believe her being inactive and gained weight after recovering from being spayed had much to do with her LP condition (or making it worse) as she started to have leg issues a little after surgery.
My past two yorkies also seemed to level out at around one year, as well. So I'd say one year, give or take, is a good average for body frame. For their hair color to mature, it may take a bit longer (anywhere from 1-3 years, depending on how fast it generally grows). And based on weight gain, again it's depending on if they are fixed or not (of course, current diet/exercise is a big factor, too). Our male was never fixed and he was muscular and never had weight issues. Our past female was fixed and was a bit chunky, but she and our male have been kept exercised, so she was fairly stable. I am more vigilant with my little Kimchi's weight because her current condition demands it (that and I don't want her to get too fat, anyways).