Just remembered this series. Quite possibly the best shoujo manga I've ever read. It just feels like it goes a step further than the typical manga. And it seems to have everything! The many different esper powers that I liked about Index and Railgun (though actually this series began either of those series!), the many inventions that I liked about Dr. Slump, the disobedient class plot thread that I liked about GTO and Hammer Session, adults who actually play a major role in the story (so it's not just kids doing their own thing), a reasonable amount of worldbuilding, SO MANY FEELS, an aging up arc, a body swap arc, and a time travel arc... I hadn't even gotten to that part yet when I found out about it from the internet—and I was like, of course there's time travel, I'm not even surprised. This series has soooo many ideas in it.
Also, Class Rep is so nice, and Luka is absolutely adorable. I love Mikan, she's so fiery. Hotaru is... well, she seems to have difficulty expressing her emotions, but she means well. And it's nice to have a super smart character in the main cast. Natsume is kind of jerk at times, but his backstory was so sad ;_;
I love this manga. Absolutely amazing, 10/10.