You could slowly adjust your light cycle so that it becomes night time. Simply change the on off time by 1/2 hour or 1 full hour every day.I don't believe that the one hour difference will cause any harm to your girls.I wish we would have started ours on a night cycle . But due to other circumstances we have them off from midnight till 6am . But next cycle we will be off during the hottest part of the day .
I originally ran my lights during the day, but did a complete 12-hour switch by giving 24 hours straight darkness. Lights went off at 8pm, I left them off until 8pm the following day and flipped them on, resuming 12/12. The plants didn't care one bit and just kept on doing their thing. I've found excess darkness is less of an issue than excess light.You could slowly adjust your light cycle so that it becomes night time. Simply change the on off time by 1/2 hour or 1 full hour every day.I don't believe that the one hour difference will cause any harm to your girls.
For the record I also prefer a night time cycle. I have complete control of light in the room so I can afford to be dark during daylight.