who made me a non existent princess???

[Complete]

I am a 16 years old modern girl who has lived my whole life in the hospital due to an unknown illness. After I've died because of that illness, I've found myself being reborn in my favourite manhwa, I read before dying, that was called "WHO MADE ME A PRINCESS"?? And I've become a character that didn't exist in manhwa, the younger twin sister of my beloved female lead, Ariana Doe Alger Obelia?? what are the chances of a person to be reborn in their favourite manhwa? My goal for this life is to die without any regret. And to fulfil that goal, I'll live my life fangirling my favourite characters.
....."Athy, I'm going to protect you from any danger that will come."???
....."Daddy is shiny and sparkly today as well"???
and other my favourite supporting
characters.

I'll rewrite the story myself, look forward!!!