i flipped my micro grow into flower ten days ago still no sign at all of sex or preflower. The strain is unknown. No signs of stress on the plant whatsoever
Now that you're girls are seeing more dark periods, they have access to stored sugars that they couldn't use during the day. So, expect them to stretch a fair bit. As for the sex you're looking real close for 2 hairs to pop. It should be real close after 10 days. Maybe upload a few photos?