Maybe she’s just a person who tries to replace cars at a certain point, like my husband is always looking at the trade in value and wants to get rid of them before repairs cost more than the value of the car. People from different backgrounds have different car theories. Plus, your car is on the older side, if she ever lived in New England, it would have disintegrated by now, you get rid of a car in 4 years from road salt.
What you would have been meaning if you’d said that and what she meant could be very different. She probably thought she was helping you find a trustworthy dealership.
Maybe you don’t have to take all of this so personally. So what if she’s well off? She’s dealing with a serious illness, and you have hurt feelings about a car you like and are worried about past polite compliments that you have no reason to doubt after a lovely dinner invitation?