anyone know about preflowering cycles?

I have 12 feminized strawberry cough that are 8 weeks into veg from seed. 2 have shown sex and the other do not. i put them into 12/ 12 anyways thinking that they where about ready to preflower and it has been 2 weeks and still nothing. i an mot a new grower but i have only delt with clones and dont know about if i have stressed them or will they just turn when ready?

i've had em go over 2 weeks and wondered if they were muties and would never show. in my limited indoor exp, males almost always show first and most that go over 2 weeks are usually female.