I play it with capo on 3. Capo depends on your range haha..
I hope you'll like this tab.

E5          C5
Give me an inch
           G5           D5
I promise I?ll take a mile
E5        C5
Danger is beauty
     G5               D5
I?ll face it with a smile

E5       C5
I?m on a mission
G5       D5
With no restrictions
E5           C5
Don?t second guess myself
G5              D5
I?m born to be wild

E5              C5
I?m the type of chick
              G5            D5
That likes to rock the beat
          E5         C5
I like to rock the beat
          G5         D5
I like to rock, to rock the beat

[Chorus]

E5   C5       G5
21st Century Girl
D5
I do what I like
E5   C5       G5
21st Century Girl
           D5
I?m taking you for a ride
E5   C5      G5
21st Century Girl
          D5             E5
Yeah, I?m gonna live it up
  C5       G5     D5
Just live it up

End E5 , C5 , G5 , and D5 goes through the whole song. :)