While primarina are most known for their more operatic inclinations (see: their signature Z-Move), they actually have different musical tastes and sometimes insist on incorporating these into their battle styles. For example, one primarina from Finland was world-famous for his exceptionally potent Sparkling Aria, which was made all the more powerful by his use of the death scream hallmark to hardcore black metal.
In short, it’s perfectly normal for your primarina to transition into a completely different genre, and by all means, feel free to nurture her interests by letting her DJ as many raves as she’d like.