by this time next week you should know the sex of your plants, the females will have little white hairs coming from the nodes(where branches and fan leaves meet stem)
use a magnifying glass to get a closer look, a male plant will have a little pod, roundish, looking thing in the same areas.
i hope this info helps. it usually takes a week or 2, but sometimes sooner, so be patient, get a magnifyer and you`ll be sexing plants like a pro in no time