@Fakhridn
Since the fist chapters it was seen and shown that she was on the 'plump' side, just being tall and a little bit prettified by manga magic. The author is a woman, so that helps Anna looking more natural. Never forget that large bosom comes in pair with an overall larger percentage of body fat. I'd say she's on the edge between being plumpy and slender, if that makes sense. She's by no means lean, though.
Then again, she's an actual model, so it's a little bit more complicated. The fact that she eats so much and still keeps her work is either a main manga gig (probably) or an indicator that she's the type of model that needs to be a little bit plushy.
I'd ask someone
professional to make some actual measurements, though. Preferably on the level of this legendary post, as this is a very curious and important topic indeed:
https://www.reddit.com/r/grandorder/comments/8hzi63/guys_im_looking_for_the_size_of_hokusai_ass/