Okay, so I watched a video for this song where Mia is performing it, and I'm 
pretty sure these are the chords. Enjoy! :-)
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                                                              MIA ROSE- LET GO 
Capo 5

(one strum for these 4 lines)
              G            C           Em               D
Every shred of hope collides in your heart
               G             C              Em                        D
with the fear of losing what you've just given up
                         G        C         Em         D
As the moments pass you pray to survive
                  G           C           Em                     D
All these lonely minutes that once kept you alive

G, C, Em, D x2

               G               C                     Em                          D
Try to change the expression that's worn out your face
                G                 C                    Em                    D
As you lose the momentum of your past living ways
              G                 C                        Em                 D
Every song is a channel for the memories to keep
                G            C               Em           D
Floating in your head as you're left asking

  Em             C              G            D
Why did I choose to let it all go
                    Em            C
was it the fear of needing
                 G                 D
or the doubts I let show
         Em                    C
I never gave up fighting
       G                D
I never said goodbye
     Em C    G         D           G, C, Em, D x2
So why? Why did we let go?

            G         C                          Em                 D
Every day is a new breath, but the battle's still on
             G             C                     Em                D
Trying hard to elude them by keeping my head strong
            G               C              Em               D
Still I feel the exhaustion of wanting your kiss
          G                  C           Em                 D
As I'm left here asking the same dumb question

Em             C                G           D 
Why did I choose to let it all go
                   Em            C
was it the fear of needing
                G                  D
or the doubts I let show
          Em                C
I never gave up fighting
      G                  D
I never said goodbye
     Em C     G         D
So why? Why did we let go?

                    C                                      G                          D
You never showed that you were scared of losing me
                          C                                 G                       D
And you didn't fight to make me stay in your arms.
D   D    D     D
So I'm left asking.....

Em             C               G             D
Why did I choose to let it all go
                    Em             C
Was it the fear of needing
                G                 D
or the doubts I let show
          Em                    C
I never gave up fighting
      G                  D
I never said goodbye
     Em C     G          D
So why? Why did we let go?

G, C, Em, D

       G       C      Em      D   G     C      Em    D
Yeah, Yeah, da da da da da, yeah
G            C           Em  D
Why did we let go?

(one strum for these last lines)
               Em              C
I never gave up fighting,
                G        D
I never said goodbye
     Em C   G          D          G
So why? Why did we let go?