I'm not sure if they're right, but these are the chords I use. For the Em and G 
chords, hold down the B and e strings on the third fret. Enjoy!

                     Dsus4
Girl, that should be me driving to your house
                 Asus4
Knocking on your door, kissing you on the mouth
                Em
Holding on your hand, dancing in the dark
                 G
'Cause I was the only one who loved you from the start

    Dsus4                          G              Asus4
But now when I see you with him it tears my world apart

        Dsus4
Because I've been waiting
                 Asus4
All this time to finally say it
                   Em
But now I see your heart's been taken
                     G
And nothing could be worse
G
Baby, I loved you first
Dsus4                                 Asus4
Had my chances, could have been where he is standing
                      Em
That's what hurts the most, girl, I came so close
                     G
But now you'll never know

Baby, I loved you first

                     Dsus4
Girl, that should be me calling on your phone
                  Asus4
Saying you're the one and that I'll never let you go
             Em
I never understood what love was really like
                      G
But I felt it for the first time looking in your eyes

    Dsus4                          G                 Asus4
But now when I see you with him my whole world falls apart

        Dsus4
Because I've been waiting
                 Asus4
All this time to finally say it
                   Em
But now I see your heart's been taken
                     G
And nothing could be worse
G
Baby, I loved you first
Dsus4                                 Asus4
Had my chances, could have been where he is standing
                      Em
That's what hurts the most, girl, I came so close
                     G
But now you'll never know

Baby, I loved you first

Em
First touch, first kiss
Dsus4
First girl who made me feel like this
Em
Heartbreak, it's killing me
Asus4
I loved you first ‒ why can't you see?

        Dsus4
Because I've been waiting
                 Asus4
All this time to finally say it
                   Em
But now I see your heart's been taken
                     G
And nothing could be worse
G
Baby, I loved you first
Dsus4                                 Asus4
Had my chances, could have been where he is standing
                      Em
That's what hurts the most, girl, I came so close
                     G
But now you'll never know
G                   Dsus4
Baby, I loved you first
                    Asus4
Baby, I loved you first
                    Em
Baby, I loved you first
    G
Oh, yeah

Baby, I loved you first