So yeah get one of those 6500k lights and put over it, keep it on 24 hours a day for at least two weeks, then change to 12/12. On 12/12 you'll need to keep it in complete darkness for 12 hour a day, thus causing it to show sex and flower. Right now, while under the light, keep the soil quite moist, but be sure the soil drains well so it's not too moist, then water every few days. Four plants is probably enough to ensure that you get a female, and more than four will probably require too much space and light once they start to get significantly bigger in a couple weeks.