The manga starts with a total recluse named Koharu, a hikkikomori NEET with absolutely no friends and little to no contact with her parents, to the point she hadn't even noticed that her mother was growing old enough for her hair to turn white. She begins to panic and tries to change but instead dies instantly, returning to her 15 year old self where she gets a chance to start over and be more social, so that she doesn't become an overly anxious mess with no friends like she was in the future. Sounds interesting, right? Too bad. Everything immediatly falls apart the moment it's revealedshe had a handsome and energetic childhood friend who secretly had a crush on her. Not just that, it is revealed that Koharu was also very cute looks wise. She has average intelligence and despite being a hardcore otaku she also has other interests and more than enough social skills to hold conversations with teenagers despite (supposedly) being a thirty something shut-in who has not had a proper verbal conversation with anyone in literal decades. Hell, in fact, because she has lived so much longer she is now much wiser and becomes instant best friends with almost every character who has been introduced so far.

That makes no fucking sense.

Every single character is just so shallow and dumb as hell, their entire personalities and lives completely change around thanks to Koharu's involvement, every single plotline so far is just Koharu coming in to save the teenage drama of the month and then getting glazed like there's no tomorrow.

The term gets overused, but Koharu really is just a blatant Mary Sue when you really sit down and read everything from a third perspective. Thing is this is not supposed to be read from a 3rd point view, this is so very clearly a wish fulfillment self-insert manga. YOU are supposed to be Koharu, this is why she has such #relatable hobbies and is protrayed like a "social outcast" at the start to make it even more easier to put yourself in her perspective even though absolutely none of these traits make sense in the long run.

She's just so friendly and energetic as well as attractive, very soon it becomes apparent that she's just a normal girl who would never have become a social recluse, or at least not to the absolute extreme as shown in the beginning. If there was some kind of explanation such as her training her skills and blossoming into a social butterfly in her late 20s her character would make a lot more sense, but she dies the very same day she tries to make a friend IRL in the future.

It's just too idealistic and wish fulfillment-y for my taste. It really doesn't help that the entirety of the cast is filled with unlikeable idiots.