No need to go look up "preflowers", unless you just want to see the difference between a female preflower and a male one. They're pretty easy to distinguish from each other if you have one of those illuminated magnification devices from Radio Shack. Pretty simple though... The female pre will look just like a tiny calyx, and if you look real close you'll see tiny pistils poking out of the top of it. The male pre will look like a tiny little crab claw, and it will gradually begin to resemble what it is, a little male flower/ pollen sac.

These preflowers will usually begin to appear somewhere around the 4-5 week old mark, and from my own experience they generally show themselves at the 2nd or 3rd node down from the main top, where the stem tissue is still soft and hasn't begun to turn "woody".

All in all, you're doing a fine job, and your plants are looking very good. Just try to resist the urge to "over-love" them... Give em a break and let them do what they do...

Peace - dooobs