Short plants with preflowers

What do i do when i have girls that are still growingand only 18inchs tall with preflowers.
do i just keep them on 24/7 until they get taller or start my 12/12 cycle anyways.

Ya can flower now or just wait until they get as big as ya want.

id flower now mate
they grow 3 times as high while in flower

If my plants show preflowers when they are 6" tall I put them into flowering. I have done it with a few plants because I dont have much space. It will lower the yield obviously but all mine is for personal so I dont care. I just try to keep a steady stream lol

Thankyou very much peeps I think i will give them another week and then flower