pollen sacks don't just pop out and release. Females usually show first.

For females, you'll see one or two white hairs, like you'd see in a bud at the junction of the stem and a branch near the top of the plant. If growing from seed, I believe it takes at least a month after sprouting to show. They have to hit a certain chronological age, 12/12 or not.

there is a good example here with a pic of male preflowers
What are preflowers? - 420 Magazine