Not like they were long. It’s no different than memorizing/remembering 99 things.
Bro it is wrong cause in each of her life she live for 20 years and she has lived like that for all her 99 lives , so she just remembered 1,980 years (edit I can't even remember the last 2 years of my life)
I thought she was never able to reach adulthood tho like even she said she only have 4 years now that she’s 14. It appears there were lives where she died before 18 and others even shorter. Ngl tho it could be the trauma, you tend to remember the happiest and the saddest memories of your life forever.
The fact that our mc remembers all her previous 99 lifes is crazy