In our program, applications are divided up between several file reviewers (students). They then classify each application with a 1-5 scale. We will then schedule interviews for those with 3 or better (I think). When you get invited for an interview is both a function of your competitiveness as well as when you appplied and when the file reviewer is finished classifying you. We also send out rejections to those who have the worst scores, so I agree, don't worry just yet!