Margaret is our narrator and main character, but she's also still a kid, so when she tells us her story, she tells it to us straight. Though she keeps plenty of secrets in this book, she doesn't seem to keep them from her readers—nor does she seem to privilege certain details over others. Check out this passage:
That night I really worked hard. I read the first two chapters in my social studies book four times. Then I sat on my bedroom floor and did my exercise. "I must-I must-I must increase my bust!" I did it thirty-five times and climbed into bed. (7.42)
Nothing says honest quite like admitting to your reader that you did exercises to encourage your boobs to grow. And we see this same forthcoming attitude about growing up throughout the book, which is part of what makes it such a great read for young people grappling with growing-up themselves. Margaret doesn't hold back, and because of this she offers camaraderie to readers who are grappling with the same questions and concerns.
But Margaret doesn't just approach her tale honestly—she also approaches it earnestly. Margaret is sincerely trying to make sense of so many things, from religion to supper party protocol, and because of this, the struggles of growing up are given the serious treatment they deserve. While a more cynical narrator might think eleven phone calls to prepare for one dinner party is ridiculous, Margaret instead relates that process with sincerity. She says:
On the day of the party I talked to Nancy six times, to Janie three times and to Gretchen twice. Nancy called me back every time she changed her mind about what to wear. And each time she asked me if I was still wearing my velvet. I told her I was. (13.45)
As far as Margaret tells it, eleven phone calls is standard practice to prepare for a social event, and her earnest approach to life can be found throughout the book.