The most impressive in my opinion is how fast you are o_o You must have become very confident in your strokes to achieve such a realistic portrait in only 3 hours (if you had to do this in like 15 hours I think your friends would have lost their patience ).
I really admire the way you've drawn hair, it really proves your understanding of how locks of hair work. You've suggested a lot yet add the right amount of details where needed. *sigh* Your work is still so inspiring !
Don't have any useful feedback to provide you, you're too far away from us, I wish you the best in your professional career, you totally deserve it