sexing??

i just moved my plant from a smaller location to a bigger one still under 18/6 and when i moved the plant it seems like it sexed into a male.. i thought it had to go under 12/12 to sex.. that possible? or wait still to see what happens

The first flowers show at about 30 days and the 5th or 6th node in the veg stage(18/6) or (24/7. They dnt have to be under 12x12 to show these pre-flowers.