HP: I’m a Transmigrated Girl, So Is It Really Okay to Be This Ordinary?

I died. I transmigrated. I transmigrated into a magical world I'd once loved very much, even though by the time the famous savior hero started school, I was already in my sixth year. You'd think this would be the start of some novel heroine's story, right? Unfortunately, I'm completely ordinary in every way, and transmigrating didn't change that. Ordinary magical abilities, ordinary personality, ordinary grades... I'd even forgotten all the important plot details... I thought my life would probably continue along in its utterly ordinary way... but right before graduation, I actually found that legendary diary... Ah, Lord Doubao, I mean, Lord Riddle, please help me out! I'm about to take my NEWTs! That was my plan, anyway. But then I discovered my ordinary days seemed to be gone for good... *Written in first person with some omniscient sections. Since the heroine narrates in first person, everything is from her subjective point of view. *A transmigrated heroine traveling through three generations: the next generation → Tom Riddle's era → the Marauders' era → the next generation. *An all-pairings story; all canon couples are broken up, but since the next generation is included, James/Lily is also mentioned (it won't come up in the main text, or will be glossed over in a sentence). *Multiple endings, with James as a separate what-if route. *Updates aren't guaranteed; I'm writing this for love. *A Mary Sue slice-of-life story. *Although it's an all-pairings story, which male leads appear depends on how the plot develops. *I only have a rough premise, not a detailed outline. I'll write wherever the inspiration takes me. I only know what happens a little earlier than the readers do. *The heroine in the blurb is in the next-generation era, but the main story will actually cover what comes after the ellipsis. *For more detailed content warnings, see the author's note in Chapter One. The author loves rambling, talking to herself, and including reference material and bonus scenes. Theme: A little Mary Sue slice of life