what i would do is keep them on 18/6 for another week at least but start introducing the flower nutes (a lil bit) to prepare for 12/12. you can top if you like or set up a scrog or LST, alot of different things to do. you can veg as long as you need or like, since one plant is showing female already you can force the rest by going into 12/12. then pull any males that show. you might wanna get some clones off that female incase its the only one. and since your hydro a bubble cloner would be perfectly suited.