I've went through your weeks. I see you ran a lot of the wks on an 11-13.
She is getting there and you did them sexing. So that in itself should of pushed them into pre.
Only thing I can think to induce flowering is to use Far Red 730nm 10m after lights out. Use a 13-11 on-off. But, if you're flipping.. she needs light to help her push thru into the next phase. But, then too much will stall and throw back into reveg, only reason there would pres is that.
Far Red will change your grow. You can add any bulb led doesn't matter once its 730nm. Look it up.