I tend to say not to defoliate so close to flip. She isn't really tall enough that your light can't penetrate either really. Your plant looks so awesome, I would flip, wait till end of stretch, then defoliate. Let that 21 days be all about going into developing flower and stretching. I always go into flower fully leafed. So that means at least 1 week after a defoliation before I flip.
Now I have used defoliation near the end of stretch to shut down the stretch. But that's because they were too tall for my space. And it did shut down their stretch.
Obviously do as you wish. Just offering my thoughts on that aspect of it. I love this grow LA.