Just do what you said, expose her to all kinds of music. Be careful though, we had a period of being stuck with South American pan pipes as a result! Make up a playlist if you have the facility to play that from a phone or tablet. Rotate CDs or program in a variety of radio stations. Ask her to guess the genre, explain what makes something country, classical, jazz, rock or pop. Ask her opinions. There are albums of music for kids that aren't kiddie pop. I remember some with popular classics. Don't expect her to like anything straight away. Just like with adults, tastes change with exposure and over time. Mine loves jazz and some rap where I don't really but I love when she develops new and interesting tastes.
