Mikan Tachibana is the central protagonist of the story, a seventeen-year-old second-year high school student who attends Kusai High School. She is the implied narrator and the character referred to by the first-person pronoun in the series title. Mikan lives with her family in a fifth-floor apartment and faces a long, stressful commute to her public high school, which does not require uniforms. Her personality is easy-going and relaxed, and she enjoys having fun. She can be both maiden-like and tomboyish, often switching between the two moods. Described as plain, timid, and a bit clumsy, Mikan also shares a resemblance to her mother in terms of exuberance and a tendency to be unintentionally rude at times. She is a heavy sleeper and struggles with note-taking, frequently falling asleep while doing homework and submitting incomplete assignments. Her interests include karaoke, eating sweets (though she dislikes chocolate cake), and a deep passion for teddy bears. She is a member of her school's Teddy Bear Brigade, a club that creates original teddy bears, performs teddy bear acts, and admires expensive teddy bear toys. Mikan taught herself to sew buttons at the age of three, and her lifelong ambition is to become a renowned teddy bear or fashion designer. Mikan's role in the story is to provide the normal, teenage perspective on the everyday life of the Tachibana family. She often serves as a foil to her mother's eccentric and frugal behavior, and the two engage in frequent, comedic bickering over rules regarding allowance, fashion, curfew, and lunch boxes. Mikan is frustrated that her younger brother Yuzuhiko gets away with more lenient treatment. Despite these clashes, she is kind-hearted and gradually learns to appreciate her mother's quirks over the course of the series. Her closest friends at school are Shimi-chan, whose real surname is Shimizu and who offers mature advice, and Yukarin, whose first name is Yuka and who introduces Mikan to cute things and karaoke. Mikan has a romantic crush on her classmate Iwaki, a stoic and good-looking boy, but her attempts to confess are often thwarted by his best friend Yoshioka, whom she has known since elementary school and who teases her. Her family relationships include a quiet, observant father who works as a salaryman and a reserved but logical younger brother Yuzuhiko, with whom she shares a typical sibling rivalry. Mikan's development centers on her gradual maturation, her struggle to define her own identity apart from her eccentric family, and her efforts to navigate the anxieties of high school life with humor and resilience. She is a dreamer who worries about her appearance, weight, and social standing, yet remains a relatable and sympathetic figure as she learns to accept both her family and herself. Her notable skills include her sewing ability and her creative talent for designing teddy bears, which she hopes to turn into a career.