There good...
Things I like:-
1. Most of its in proportion...
2. The colours you have chosen look Nice together
3. The clothing and detail you have added is great
Things I think you should work on:-
1. When shading try to avoid the Graidient tool...
(it makes the drawings look flat in some area's, like the hair)
2. When shading shade in the direction of the curves and body stucture
(Try to imagine a light above your person and where the shadows will fall)
Your 20 years old and your drawing is great, I can tell you drew these using the mouse and not hand drawn by pencoil and scanned in... to draw this good with a mouse takes talent and I am sure your better with pencil and paper... Investing in a scanner to scan in your pictures could be worth while...
I like em !!!
This is my fav thing I found on there...