>>2405896My point is your argument is entirely subjective, now I'll play the devil's advocate for a second here your argument would hold more ground if the Artist included some form of narrative that the figure he drew is "x" age; however if there is no narrative of age we're now in the realm of speculation and based on context clues such as child bearing hips, visible breasts (despite the size or DFC), fat pads around the naval area, etc. we can say that she is a mature woman with supporting evidence.
In the case of Murata we have figures with quite visible breasts, feminine fat pads, and characteristics of a woman.