Autoflower does it automatically, even with 24/0 lighting (many strains). Feminized - 12/12 is good for flowering! All strains need proper nutrition for their age! You will feed the plant during flowering as "for flowering" according to your nutrient charts!
You immediately switch to 12/12 and change the schedule. If it's soil - flush according to the technique and use flowering nutrients. If it's coco - just pour a new set of nutrients in the watering according to your nutrient feeding schedule and wait! White hairs appear at the growth points - flowering has begun! 👌
Good luck, friend! ✊😇