I haven't read a pooping fic this good in a long time! Your introduction is great. You worded it well, and the whole "girls don't poop" concept is a good way to start off a pooping fic. Your comparison of pooping at school to scary creatures is also great. The rest of the story is also very good. Few fics here depict a high school girl, her thoughts and actions, in such a believable, high-school-girlish fashion. This authenticity made it all the easier to imagine the cute high school girl unloading her massive cargo. You paint a vivid picture of her trying to concentrate while desperate. And you cover all the bases by describing her messing herself (in her imagination) and using a toilet (in real life). And both are nice and detailed, although the real dump is where the real fun is. You also pay a lot of attention to her wiping, another rarity in Nyou fics.

Now for my criticisms. Gas doesn't move through a colon that fast, for one thing. But my big problem is that you don't describe Kaitlyn's looks, except for her age and her cheerleader-worthiness. We don't hear much about her clothes, either. A detailed description would definitely increase reading pleasure, especially if you kept it up through the narrative. Like, saying how her face was reacting to various stages of desperation, or what she looked like scampering over to the public toilet. Some dialog with her friends and other "background" details about what was going on in her classes would also help.

All in all, this is a very promising first story for you. Keep writing!

I liked it. Quite a nice little tale. My only critique is, her load could have been bigger. But I'm hard to please in that area :p