Need your feedback: Color or mono?

In this case i would go with the B&W. She doesn't have a lot of color to begin with (grey & black clothing and dark tree). I might go with a portrait crop as well. Not a lot of interest or complementary things in the background. You might even consider masking the gold necklace to add a touch of color? A lot depends on what you want as a final outcome and time to spend on it.
Gee Dub

Thanks for the feedback. I decided to go with black and white, as the background is uninteresting. I tried the portrait crop, but it took too much from the picture. What I'm doing is centering her a bit more on the frame. I'll give it a try and will post the results.

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Coming from edvphoto blog (?)

It usually is a mistake to "Center" the primary subject. Makes it too stiff and uninteresting, I would move her more to the left and have more of a darker background and maybe punch up the highlights to bring more interest back to her face, maybe even try to bring more of her hair out. My suggestions is just PP as I like to say. PP is personal prefference to me and Pee Pee to you ;-)
But you did ask so I try to help out.
Gee Dub