Alternating growth started

Hi, I have several plants growing outside. Six are as tall as I am, they were planted in better soil than the others.

Anyway, I'm on the 44th parallel and 4300 foot elevation (NE Wyoming). Today I noticed that the new growth is coming in on alternating sides, instead of Y pairs as before. I know that means sexual maturity. How long till I should be able to sex them? And how long till they flower?

Thanks.

You want to watch for calyxes with pistils (female) or pollen sacks (male) appearing at the nodes of the branches.

How long till they flower depends on genetics. Once the days start to get shorter is when photo period plants start to bloom.