The age discrepency bothers me. In the first few pages its mentioned that "She's 4 years younger than me, she's barely 14 years old" which should put Hana at 13 or so right? And then MC 17 or so.
But MC is 21 before her body's clock is rewound to 15. Which means in the hospital bed Hana should be 17 years old.
I hope im not misunderstanding things. But the age counting is off. The story seems lovely so far. Thanks for translating the first chapter.