This book literally has Margaret's name written on it, so it's no surprise that what we encounter throughout the pages is Margaret's story. And who better to tell Margaret's story than Margaret herself, right? We think so anyway. From the very start of the book, she's an earnest and honest narrator, sharing herself freely with us as readers. Check it out:
Are you there God? It's me, Margaret. We're moving today. I'm so scared God. I've never lived anywhere but here. Suppose I hate my new school? Suppose everybody there hates me? Please help me God. Don't let New Jersey be too horrible. Thank you. (1.1)
Right away we are pulled into Margaret's fears and anxieties, and also allowed to witness her otherwise private chats with God (not even her parents know about their regular conversations). This keeps our loyalty firmly in Team Margaret, so as other folks battle it out to sway her to follow their paths—particularly when it comes to religion—all we care about is Margaret finding her own way. We know how much her talks with God help her because we get to eavesdrop on them.
By positioning Margaret as our narrator, Judy Blume sets Margaret up as the norm. She is our eyes and ears throughout the book, the person who helps us make sense of her experiences as they happen. So while Margaret is different from other kids in Farbrook, New Jersey and other members of her family, since she hangs out at center stage for us as readers it's everybody else who ends up seeming a bit off. Cool trick, right?