The fact that you're 20 years old will blow those selection committees away! Because of your age, they'll understand that you're super intelligent, but really haven't had the time nor the opportunity to get published. However, you have a low writing score on your GRE. Being published would offset this, but since you're not I suggest that your essays and SOP's be flawless. Seek the help of professional essay writers at EssayEdge or a similar group to look over your work and offer pointers. I suggest doing this rather than having your professors read over your essays. Find someone who does it for a living to help you out. Good luck!