I would say you can choose to or not to pursue your purpose, but curious more about the origin of purpose. My initial thought was that purpose comes from what you are exposed to at a young age. I was thinking about the Polgar sisters because their dad raised them to be pro chess players. But I was thinking, they easily could have rejected it as they got older. It is hard for me to piece together if they are representative or sort of an anecdotal case.
An example that I was pondering in the other direction is Steve Harvey, who found comedy later in life and considered it his purpose. But he does say he knew he wanted to be on TV even as a kid, so there may always have been an element of wanting to entertain.
EDIT: If context helps – this question stemmed from thinking about a Viktor Frankl quote, “When a person can't find a deep sense of meaning, they distract themselves with pleasure.”