Just spotted some images uploaded by a forty-something model which caught my eye. Very nice face and figure, good poses, experienced etc. Looking pretty spectacular in fact.
Looked a bit closer and realised a lot of the images by one photographer at least were so heavily photoshopped that all skin detail had effectively been obliterated. I know the photographer in question and his work isn't usually so 'smoothed. That said he generally shoots younger models with one or two notable exceptions... The images weren't liquified to any great extent that I could see, so her figure was pretty much as portrayed.
My though was this - why shoot a forty-something model and then spend hours trying to make her look 20-something (obviously if the model asked for that look it's another matter, but since not all images in her port were in that style I am assuming this wasn't the case)? Looking at the images in her port that were't so heavily retouched, you can see she's had kids and that time has left its mark, though not in a bad way.
She appears as a fit, healthy and attractive woman.
If you like the look of a model then celebrate that look - don't make it a lie... There are several forty-plus women on this site who are exceptional models - but they don't look like teenagers and in my mind shouldn't be 'shopped' to appear so. If you want a young-looking model, hire a young model - if you like the look of an older model then book an older model. If your idea requires a certain look, book a model appropriate to that look rather than trying to fit a square peg in a round hole.