I kinda forgot what was her secret again? 💀

I think it's that's she's suffering from a mental illness? I don't really remember too well either

yeah, you're correct, it's that she has PTSD and collapsed from it and was depressed, they view it as a huge defect

Her secret is simply that she suffered from mental issues during the ages of 16 and 20. Like Raul told Carcel in ep43, she snapped out of it at age 20 and has been basically fine ever since. She was also basically fine from age 6 through 16. It’s just those four years that she went through a mental breakdown that will reveal the truth later on. Why she experienced that and what she experienced is something that will be told from her pov in the future.