The construction of the face is very well thought out- the expression is gorgeous, the eyebrows slant at just the right angle, and her pouty mouth sells it. I love the way the hair is textured, it seems that each individual lock is openly visible, good job!
The only real negatives that I can see with this piece is the overall anatomy of the entire left arm and the right hand, respectively.
Otherwise, this piece is gorgeous; I wish I could sketch human faces so well!
Keep doing what you're doing, I just know that you're gonna get far if you carry on!