That's an excellent point about how people may interpret the saying in two ways: as small-c or capital-C "conservative."
The challenge for journalists like me is that the only way to figure out whether or not the saying true is to look at something measurable, like voting behavior. I'd love to know if there are any surveys that measure what happens to small-c conservatism as you age, which I didn't come across in my research.
I also appreciate your perspective on the different meanings of "Republican." Thank you!