Oops I Did It Again by Britney Spears is played in the key of C#m at a beginner difficulty level, originally released in the 2000s. It uses 2 chords — C#m E — arranged in the i-bIII progression.
About the i-bIII progression
This song is built on the i-bIII progression. Follow the chord order in the diagrams above, and use the transpose controls if the key doesn't suit your voice.
Playing in the key of C#m
C# minor is another barre-heavy key. Capo the 4th fret and use A-minor shapes as a friendlier alternative.
Related songs
More songs in the key of C#m
Learn to play Oops I Did It Again by Britney Spears on guitar. It sits in the key of C#m and uses the i-bIII progression with the chords C#m E.