Sharon, a young girl

I think the expression is endearing and compelling, soft and extremely engaging. The framing and light helps support her nicely rounded face, the slight turn of her head and angle of her shoulders is classically conceived without being obvious or feeling staged. Considering your noted feelings of sensitivity from this teen, and even without your saying so I'd agree there's a lot of sensitivity in both her eyes and lips, the darkness of the shadow feels a bit extreme to me. For me, it might be more appropriate to a scary feel or a film noir feel that was trying to get at some kind of anxiety or a darker emotional state. For a  young woman of this age in this type of portrait, I can understanding giving the photo some contrast and that lighting certainly adds to the overall feel and depth of personality, but the blackness on her face just seems a little to graphic and gone for the rest of what I'm looking at and experiencing. Even very dark shadows can still allow for the feel of the skin and contours, but this shadow seems more harsh and invasive than that.