Pre-Op means that you are Male > Female. So that means that the person still has a penis and testicles.
A penis and/or testicles means that she will go to Male Prison.
It makes no never-mind if the person lives full time as a woman or not... If she still has her penis and/or testicles, she is legally still a male.
Your gender is still legally what you have under your pants. Until the surgical procedure is completed, SHE is still LEGALLY a HE.