Yes you were confused. The first chapter is actually the aftermath of the story.
Pretty sure the first chap is like a sneak peak of the future right (like the future of her second reincarnation, where she tries to change things)?
Chapter one is her new future after the reincarnation
The first few chapters are the original future. When she dies she decides to change that to prevent the fall of her family. The future now that things have changed are going to be different.
Just to know if I got this right: Tia and Perez were lovers before she got reincarnated right?? They were about to marry in the 1st chapter? (Am i confusion???)