I like the pose and the eye contact. Agree with Axel about the crop and additional sharpening. I don't usually find the 100-400 all that sharp at f/5.6. It doesn't seem like you had enough light to stop down. Thanks for posting!
I agree with Axel and Doug re sharpening. May rotate CCW as what I assume is water bottom left is sloping significantly. This is a very nice portrait, Emily. Here is a version with some rotation and sharpening. This has accentuated some cloning work around the back of the head and neck.
Good job, Bee. Just a little more time smoothing out the vertical lines in the extended canvas. I find the clone stamp in lighten or darken mode at a low opacity useful for this.