To start, most people usually go with 18/6 for veg. Then when they want to force flowering, they switch to 12/12. I don't want to discourage you, but you sound like you're not really ready to grow.

Some people start 12/12 right from the start, so you can do that. But if you want, you can put them in 18/6 until they grow up a little and then back to 12/12 to force them to flower and show sex. I'm assuming that your plants are still too small and have not shown sex. Let us know if this is not the case. I don't know if you know it or not, but you only want to grow females, cause males don't have any buds and don't even get you high.