Heres a pic of some preflowers to help determine sex of the plant. (First pic)
Female on the left side, male on the right side.


The second pic is my first female, with VERY early pre-flowers starting to appear. This plant is 31 days old today.

I have noticed on my female plant (which is currently still in veg) that the calyxes started appearing at the top nodes and are slowly starting to grow their way down the plant. I think thats pretty normal for them to appear that way when the plant begins to show its sex.