Here is a slip-up I found. In book one it says that Elizabeth, one of Alice’s friends, gets her ears pierced so that she can wear hoop earrings to complete her Halloween costume. But, in book four, Elizabeth says that she will never pierce her ears. Here are the exact quotes from the books.
The Agony of Alice, Book 1
Chapter 8, “Bringing Up the Rear,” page 61
For a week before Halloween, that's all the girls talked about. Elizabeth Price's mother was making her a gypsy costume. She'd been working on it since September, Elizabeth told me. The skirt had three ruffles around the bottom in purple, pink, and green, the blouse was red, and there was a purple satin vest with sequins on it. Elizabeth even had her ears pierced so she could wear some hoop earrings.
All But Alice, Book 4
Chapter 4, “Zombie Girls,” page 42
“This is so gross!” said Elizabeth. “I am never going to pierce my ears as long as I live. I don’t care if boys never ask me out. I don’t care if I’m the only one who doesn’t go to the prom. They’d have to knock me out and-”
Chapter 7, “The Earring Club,” page 74
“Where are you going?” Elizabeth asked when she saw us heading away from the school bus.
“Earring club,” I called to her. “Want to go?”
“She can’t,” said Pamela. “Tiddly Winks carries only pierced earrings. They don’t have any clips at all.”