Sexing a plant.

Does the sex only start showing up when you put it in flower? Does is ever come in veg?

And also, what is the sex of these plants? I think the first one is male, and the second female or hermi. Is there anything good that can come from a hermi or just get rid of it?

#1 looks like a male. Preflowers and pollen sacks can show up in veg. #2 has a pollen sack, can't tell for sure what's behind it.

1st looks male 2nd looks female

How do I know for sure? How about the hermi questions?

1st one is a male and the second is a female

need to get rid of the male if you don't want it to pollenate the female
the male has like little balls where the branches meet the stim
and the females have two little white hairs coming out of the top, where the branches meet

keep em green

Early pollen sacks are on stalks, flowers never. Unless you want to make seeds get rid of it if you have other female plants. If not grow it out and you will get seeded weed which can be very good. However, some of the pollen will remain in your grow room and may have an effect on future grows.

Here's what I'm seeing that looks like a stalk. Looks like pistils behind it but I can't tell for sure.

If the "female" one was a hermi, would i already see sacs next to the hairs?

well i just had a hermie and didn't see mine for three weeks into flowering
but i don't know if you would see them right away