My female training group doesn't have anyone like the older female you described, though perhaps I fit the age, being 57.

I don't get why others have to make comments, don't like it when it is directed at me by totally strange cyclists either. I personally don't examine other cyclist's bikes, other than to put in a mental category of road bike, hybrid, comfort bike, mountain bike, etc., and maybe note the color. It is an individual choice as to the bike, clothing, etc., and so there is nothing for me to observe and thus nothing to comment on.

I can say that for young fit females, it doesn't matter what type of bike they ride, because most of them can zip by me on the hills like I am not moving at all, have incredible endurance and are really strong for speed. When they are able to upgrade to a road bike with clipless pedals, even at the entry level, from a mountain bike or hybrid, just like that they are completing steep category climbs, metrics and full centuries. I've observed it at least 3 times this year alone between my two training groups. I am cheering for these ladies, not being jealous, because they all found a sport that gives them a passion and I am excited that biking will be a part of their futures.