After school it's the first meeting of the secret club. The other members are Nancy, Janie Loomis, and Gretchen Potter.
The girls gossip a bit, and then get down to the complicated business of picking a name for the secret club. After heated debate, Nancy suggests the Four PTS's (Pre-Teen Sensations) and everybody agrees.
Of course you can't have a secret club without secret sensational names, right? So the girls (but really just Nancy) choose Alexandra, Veronica, Kimberly, and Mavis for their Four PTS names… and Margaret gets stuck with Mavis.
Now it's time to set some club rules. Nancy's rule is that they all have to wear bras, Gretchen's is that the first to get her period has to tell the others what it is like, Janie says that they have to keep a Boy Book, and Margaret decides that they have to meet at the same time each day.
Margaret's rule stirs up a lot of discussion as everyone tries to find a day that works, and the fact that Gretchen has to go to Hebrew school brings up the religion question.
In response to the question of just what is she, Margaret tells the story of her parents: "Well, my mother's parents, who live in Ohio, told her they didn't want a Jewish son-in-law. If she wanted to ruin her life that was her business" (5.66).
So Margaret's mom and dad eloped, and decided that Margaret could choose her own religion when she got older.
The girls are confused though—if Margaret doesn't have a religion, how will she know if she should join the JCC or the Y? Margaret doesn't have an answer.
That night Margaret manages to ask her mom for a bra, and then she has a little talk with God. She asks for a some help in the growth department, now that she's gonna be wearing a bra and all, and then she gets down to the tricky business of choosing between the JCC and the Y.