It’s pretty common where I live, especially for people who grow up in conservative families. You start out assuming the trusted adults in your life are right about everything (or at least I did), but once you’re exposed to the world outside your bubble, you gradually (or not) change your mind on a lot of things.
I get that that’s different from, say, an adult with fully formed beliefs one day changing their mind, and that probably is pretty rare. Still, out of all the badass lefties I know, most of them did have at least a few years of cringy hardcore conservatism. 🤷