Newbie here. Young plants in Veg. and Clones in Veg. under cfl's

I have some 5 week old plants (S. dominant strain and the plants are very healthy looking: big thick stalks and plenty of branching) in under cfl's in my living room on 24/0. The thing is, they started flowering, but they're still growing rapidly. I think the flowering happened because the plants haven't had, until now, any sort of reflective material surrounding them and they're sitting in my living room so they're receiving less light during the night. I live in Alaska and we just had our summer solstice with very little if any darkness, but there is a considerable change in the amount of light that comes in through the windows at night compared to the day time. Anyway, I'm wondering if this is have a negative effect on the plants. I've been growing from seed until now and wanted to take clones from one of these females to make a mother plant, but I'm not sure when to take the clones. I'm under the impression that taking clones too early will only produce short, not fully mature, healthy plants which is why my plan was to kick the plants back into the Veg. stage and take clones when the plants are more mature. Is this true? When would you recommend I take clones from this batch of young plants?

Also I was going to take clones just to determine the sex of the remaining plants that didn't flower. I was wondering if the clear plastic lid covering for the clones is a must. I plan on getting one for the official clones, but can I get away with out it with these?

your plants are either autoflowerers which sounds unlikely or the change in light at night is significant enough to trigger flowering. in any case you need to set up a light proof area that you can keep completely dark for 12 hours of the day or you are going to have a hermie farm. you need to get this fixed right away.

as for clones, take them anytime you can get a decent sized cutting, a clear plastic lid is not a necessity but high humidity is and a dome is one of the easier ways to keep up the humidity.