It could use some detail, especially on the left side of the screen. The colors don't look very nice either. The right hand is weird because some of the lines are in a different color. The lines could be cleaner too, and that extra line under the "Newgrounds!" shout seems unnecessary. The face is pretty nice though, and I always appreciate NG-themed art. My advice is to keep practicing. You're only 14, so you've got a lot of time to improve.