My 20th Twenty

So Won was born in 1981, so she should be in her forties now, but when she became twenty in 2000, she encountered a witch by chance. So Won was cursed by the witch because she turned down her favour. The curse was “to live as a twenty-year-old woman for the rest of her life.” At first, she thinks it will be a blessing but soon suffers from the pain of losing her beloved ones and making no progress.