When did your cat "fill out" ?

[haleyds]

My girl is around 15 weeks old now, and in my opinion she looks very lanky and thin. She's a purebred Himalayan but her fur is also not quite as fluffy as a typical Himalayan, but it is the proper length and all that. Looking back at pictures of her litter mates, they were all fluffier and more stocky like. I have her paperwork and saw both parents multiple time so I know I didn't get INTENTIONALLY duped, but I'm just wondering if she will "fill out" with either fur or weight?
She has a great appetite and eats good, I brush her daily which makes me wonder if I'm slicking her fur down maybe.
Orrrr on the rough side is it possible she had a Siamese sire by accident??? The breeder she is from had a male Siamese but I'm unsure if he was neutered or not, I'm very aware that if he wasn't then it would be entirely possible that they could have gotten together without her knowing. I would hate to confront her about this because I'm not breeding/showing my girl and I love her as is.
Any insight would be very useful.

 

[haleyds]

Trying to post pictures but they currently don't want to embed. [emoji]128580[/emoji]

 

[detroitcatlady]

15 weeks is very young, many kittens will not "fill out" until they are a year old or so. I have one cat who is just over a year who is just starting to fill out and has always been thinner than most and another who is almost 2 who was about full grown at 6 months. Some breeds are known to mature late but it won't always be the same for every cat. They all mature at different rates and some just happen to fill out sooner. As long as she isn't underfed and you can't feel her ribs I wouldn't be overly concerned. I don't know much about Himalayans but I do know that Siamese are not the only breed that matures late. If she was Siamese, her hair should be noticeably shorter than her littermates, at least I would think it would be.