Is this the pre flower stage?

Plants preflower when they reach sexual maturity. It will only begin the actual process of flowering when the light cycle is 12/12~ (or if it's an autoflower, of course). Does seem to me like there is indeed some female preflowers kickin about on there. You don't have to do anything specific, it's simply a sign that it's sexually mature (and some positive reinforcement if you're popping regular seeds)- Keep filling your space and flip whenever you're good to go.