Is being fictionkin a choice? Or are you born that way?
Consciously using the label of fictionkin and identifying yourself that way is a choice***. But you can’t just decide to turn yourself into a fictionkin (or an otherkin or therian). People who say that you can decide to be kin and just ~make it happen~ are lying, and trying to change what our communities are in order to justify their power fantasies. Which is silly, because everyone can have fantasies. There’s no need to call it kin to make it meaningful.
But in general I don’t like applying the Born This Way logic to it, because that’s really tied up in lgbtqia politics, and I don’t think it’s appropriate to bring that here.
(***one of my partners recalls a past life that he shared with Nate in a fictional universe. But he doesn’t feel much attachment to it, and so he doesn’t identify as fictionkin even though it defines what he’s describing. He’s just a demon, by his own identification. In that way, it can be a “choice”.)