So, you have a great modern camera and a great lens.
I have simulated the DOF and I made a crop of this one from the screen. Not from Cambridge in Color (which I should study because it is very sophisticated) but from DofMaster and I calculated in meters.
I could have done in feet but ...
As we can see the DOF is only 0.18 meters. Sufficient, more than sufficient for a face. May be you have focused on the wrong place or the young girl moved a "great" bit.
Why don't you try again - it seems I am a teacher which am I not in fact and don't intend to be - making an Adjustment Brush (LR) or an Unsharp Mask (CSn) locally, only on her right eye ?
I have done this table once to be used with the 20D.
I have even "built" this round table which could be used on the crime scene !
And you know what ? I have never used it !!!!