Could be too early, but Is that some signs of the plant starting to bud at the bottom of pics 2 and 3? If so I'd say it's a female..other than that, it's kind of hard to tell..take pics closer to the stem.
the third picture is female. The other two i'm unable to tell. View attachment 2650316 I marked where I see little pistols (Upon closer inspection, the first looks to be female too.)
auto-flowers will flower within your normal veg hours (18/6 or 20/4 or 24/0) ...so no need to switch to 12/12, but you can if you are concerned they may not be auto-flowers
If you really really really want to know you can force sex them by going 12/12 then when they show bring them back to 18/6. Otherwise, just wait and they will eventually show.