Ultimately, it's up to each person whether they watch the movie first or the series. Jujutsu Kaisen 0 is not just a prequel in the storyline but is based on a manga that was written before the actual Jujutsu Kaisen manga that led to the anime.
Here are five things you need to know before you see JUJUTSU KAISEN 0!It's A Prequel Film. ... Anyone Can See It. ... It Has A Superstar Main Cast. ... There's An End-Credits Scene. ... There's Plenty Of Satoru Gojo To Go Around.
For the casual viewer, simply going to see the film might not be as enjoyable without context. So, like Mugen Train, Jujutsu Kaisen 0 is also canon. It's adapted straight from the manga. But unlike Mugen Train, and as its title slyly implies, Jujutsu Kaisen 0 is a prequel.
The Series, Jujutsu Kaisen Age Rating is TV-MA and 16+ Age Rating on Netflix for Violence.