I had to look at this for a younger relative a while back. The main character is definitely Nikki Maxwell. She's this middle school girl who starts at this fancy private academy, Westchester Country Day, on an art scholarship while her family isn't super wealthy. I remember thinking the whole setup was pretty relatable for its target audience. She's got massive social anxiety, especially around her mega-popular arch-nemesis, Mackenzie Hollister, and spends a lot of time stressing about fitting in and not looking like a total dork.
The diary format is the whole thing, right? So you get her super dramatic internal monologue about every little embarrassment, like a major crush on Brandon, or dealing with her little sister. She’s creative and draws all these little cartoons in the margins, which gives her a bit of an edge over just being the shy new kid. Honestly, sometimes I found her a bit whiny on a re-read, but that’s probably because I’m not twelve anymore. For a kid, that over-the-top reaction to social stuff is probably the point.
The series really hinges on her perspective. Everything feels like a huge deal because it’s through her eyes. She’s not the cool kid, she’s the one observing the cool kids and trying to navigate it all without dying of embarrassment. The appeal is totally in that specific, exaggerated middle school mindset where the social hierarchy feels like life or death.