Pre flowering or not

[rjlp16]

I'm a new grower and I have three plants that I'm not sure if they are in the pre flower stage or not. Can anyone tell from my photos if they are?
They were grown from all feminized seeds and are Sativa plants.

Thanks for any feedback

 

[v3gas4ce]

These look pretty much like calyx + pistils.

 

[labexperiment]

How old are they?

I would say not quite yet.

 

[MaPilot]

I would say give it a few more days, You want to see some white hairs (pistils) sticking up through those stems (stipules).