As long as flowers don't grow, it is not a problem.
If these are your "beckys clones" and were taken from a sexed, mature plant, the preflowes will always be there, it is not a sign that she will flower, just a sign that she is sexually mature and ready to flower once the light is changed to 12/12.
However, you should never grow at 24/0, all cannabis plants NEED "sleep" for a correctly functioning metabolism and to finish their daily photosynthesis cycle.
18/6 is optimal and the healthiest schedule for your plants.