If you've been flowering for 3 weeks and your plants ain't showing sex, you probably aren't under 12/12 lighting. Where ever you have them must be getting light to stop the flowering process. If you don't have them in 12 hours of complete darkness they will not flower. Make sure you seal the closet. Using black and white plastic you can put some overlapping flaps to block light. Just make sure it is light proof. Stand inside the closet with the lights off and see if you can see any incoming light. If you can fix it. Once you are outside the closet have the closet lights on and room lights off. If you see any light even pin holes get some duct tape and seal it. You should notice a difference.
No offence, but you seem to be needing a lot of stuff. It's never a good idea to be taking plants from outdoors indoors. You can bring in bugs and diese to your grow room. Having plants outdoors is always a good thing (assuming security is not an issue). Sun light is very powerful and we can not trully make an artificial light that compare's to its power. I grew bag seed many times to learn to grow. I would reccomend new growers to start that way. If you are going to make mistakes then make it on something free.
For your flowering question. I usually veg my plants for about 2 months first. I like my plants fully mature before I flower them. My males usually show sex in 2 - 5 days. My females usually 4 - 8 days. I have had some very good crops from bag seed. I still have an 4 year old dad that I keep around to breed with.
Good luck.
