I have always associated the high waist, muslin, white, with youth and Summer. Thank you costume dramas. Obviously in my personal universe this is possible but not in the everyday world. In some vague way I'd assumed that there were different modes of dress for different ages as well as status.
Do I want to be seen dressing like my mother? Would she wish to dress like me? How would we look in the clothes and styling of an 18 year old?
In the Mirror of the Graces the idea is that young and old follow the same fashion with only minor adjustments to cloth, colour and degree of ornament. Don't think Goya agreed that was a good idea.
I have been trying to find as many contemporary portraits as I could showing older ladies to compare. Not a rigorous investigation but interesting to do. Conclusions so far are flimsy in the extreme but the some of the portraits are entrancing.
These two ladies look younger than the ones above, more of middle age, but both are dressing in the fashion. The covering of the throat seems to be a desirable thing - even when the dress is the fashionable low square cut, the chemisette is all but invisible apart from the ruff. I have seen designs like these on willowy, sylph-like models on the fashion plates.