I think that this quote reflects much of where Melinda is in her first marking period of high school. There is much in way of "silence" between Melinda and her former friends. Eye contact is the only way she is able to "speak." The fact that the quote stresses that this manner is the "best chance" she has is a reflect of where she is socially. At the same time, the quote says much about silence, in general. The fact that Melinda knows that her friends have to "decide to talk to me yet" is reflective of how much in silence Melinda lives after the events of the summer. Essentially, Melinda has undergone two violations. The first was caused at the hands of "IT" at the party. The second was the social isolation she experienced as being tabbed as the one who "called the cops."
Due to both realities, Melinda lives in silence. the significance of the quote is that it shows how much of a state of being this was for her. She is not able to initiate conversation with much of anyone and feels that she has to wait in order to "speak." As her Freshman year progresses, this will change as she will change.