In Jerry Spinelli's Stargirl, when and how does Stargirl first become aware of Leo Borlock?

In the prologue entitled "Porcupine Necktie," Leo tells about the time he read about himself in the family section of the local newspaper that highlights birthdays. In that article, his mother reported that Leo had a porcupine necktie collection as a hobby. Leo was fourteen years old at the time, which probably would have put him in ninth grade. A few days after the article about his hobbies ran in the newspaper, he found a birthday present on his doorstep and discovered that it was a porcupine necktie. It isn't until later in the book that he discovers it was Stargirl who had given him the necktie. He doesn't meet Stargirl until he is in eleventh grade, though, which is when the two of them are around sixteen or seventeen years old. Therefore, Stargirl first becomes aware of Leo Borlock when they are in ninth grade through the newspaper article, but the two of them don't officially meet until a couple of years later in eleventh grade.