Grease: Rise Of The Pink Ladies is a prequel to 1978’s Grease, but how long before the original movie does the prequel series take place? Set prior to the events of the musical movie Grease, Paramount+’s Grease: Rise Of The Pink Ladies tells the origin story of one of Grease’s main greaser groups, the Pink Ladies. Following a cast of all-new characters who attended Rydell High prior to Grease’s main cast, the prequel perfectly sets up the events of Grease.

https://screenrant.com/rise-pink-ladies-timeline-how-long-before-grease/