Why Is the Dream Girl Fanfic Heroine's Character So Ordinary?

Mirabelle is an ordinary child. While her friends transformed into magical girls, collected cards, and purified villains, she did math homework with her classmate who lived next door. While the kid across the street and his childhood friend took things apart at a tender age and set their sights on becoming Chief of Police, she memorized language lessons with her classmate who lived next door. While her little brother, a genius with an IQ of 218, built robots, she worked part-time with her classmate who lived next door. While her second little brother used his psychic powers to reach the moon, she talked with her classmate who lived next door and the friends she'd met outside about where to go to high school. Aside from a family history as complicated as Thunderstorm, and an ability that's just a tiny bit special but nowhere near as impressive as magical girls or psychics, Mirabelle thought she was the most ordinary child in the world. But that belief was completely shattered after she entered high school. Many years later, Mirabelle was sprawled on the sofa, Coke in her left hand and potato chips in her right, blatantly slacking off and ignoring her work, when it suddenly hit her: She'd somehow become a classic shonen manga villain. And she'd led a whole bunch of protagonists astray. A few notes before reading: 1. A Yuuji and Geto x original female protagonist self-insert fic. Consider this a major OOC warning. (The plan includes a foursome with Shoko, but she's a bit hard to write (really hard), so we'll see how things go. (If nothing goes wrong, it's probably still happening, yeah (you). 2. The timeline is a chaotic mix. I really did my best. ( 3. It's probably a slice-of-life coming-of-age story (what?). The timeline runs from third grade all the way to adulthood. How long it gets depends entirely on how much I can pad it out (?). The female lead will eventually become one of the top sorcerers, too. Her cursed technique seems pretty overpowered. ( 4. I'm bad at coming up with titles and writing blurbs, so I just made things up. The actual story might have absolutely nothing to do with either of them (sorry). 5. Any setting that doesn't match the original work is my own headcanon (for convenience). 6. No chapters in reserve and no outline, I'm winging it, so don't trust the blurb. The story itself is what counts. 7. This is seriously, seriously, seriously not for everyone. Readers, be cautious before diving in (be careful). P.S. The author is a parenthesis enthusiast, so I really like using parentheses. Gomennasai. Help, why am I still so bad at writing blurbs?! Theme: Hahahahaha, how wonderful, how wonderful