The plants are probably still sexually maturing. If it was grown from a seed it will have to be around 6 weeks old to show sex, maybe 8 weeks. Since you cut the light back it might slow down the maturity a bit but it wont hurt anything. Its reccomended to wait until the plant shows preflowers prior to 12/12 light cycle. How old are the plants? Are they from clones? It will flower soon, I wouldnt worry.