It's common, I think, to learn the rules of grammar, become a linguistic prescriptivist, and then learn about dialect and evolution of language and become a linguistic descriptivist.

Sometimes I feel like the latter correction overcorrects, and becomes something like "you're not allowed to have opinions about how people use language, or exert pressure to try to get it to be used in a particular way". But of course the process of language evolution you just learned about is exactly the result of people doing this! You relate to it a bit differently from the prescriptivists, as a language designer rather than a blind enforcer, but you have as much of a right to do language design and advocate for your design as anyone else.