trying to find out gender

Now that my first plants are a month old can i put them at 12/12 a while to sex them? then bring them back to veg state? I'd like to get rid of the males for more room.

Yes, you can do that, but why not take clones and then sex one from each plant Then you can discard all of the males and flower the remaining female clones. By doing this, you'll get some mother plants. Eventually, you can weed those out and just keep your favorite females. You also avoid stressing the plants.