I want to start a story about a 18 year old who gains the power of of invisibility by scientific means. It will be pure ENF and a more humorous story. Should I pick Science Fiction, Humor and Satire, teen, Non-Erotic, or something else?
There are a number that fit. If you plan to make the humor a focus, Humor and Satire could be a good way to pull in viewers who'd appreciate it when it appears on the list. Personally, while I understand the thought, I'd avoid Non-Erotic for an ENF story. The most useful thing to do for yourself is to put yourself in the reader's shoes and think which applicable genre best sells a strong aspect of your story when it pops up on the front page. My advice, though, is not to worry about it too much. From my perspective, I never search the genre classification. I don't think it'll be a thing that makes or breaks your story's findability compared to a good title, hook, cover image, or tags.
I know ENF and exhibitionism are different, but most stories like that end up in exhibitionist & voyeur.
The category matters most when readers specifically search for stories by category. This means that, when you choose a certain category for your story, you're choosing to market it towards a certain group of readers. Nobody would specifically search by Non-Erotic to find a story that's still sexual in nature but lacking actual sex scenes, so I would avoid that category. How important is her age to the story? If it focuses on her life as an 18/19 year old and the specific conventions that come with that, especially finishing high school and starting university, or exploring her sexuality for the first time, then Teen might be appropriate. It's probably not, though. It sounds like the sci-fi aspect is just an explanation for her origin story. It's extremely common in CHYOA stories to justify their premise with something that's technically considered science fiction, like "X event happens in 2025" or "Y futuristic technology exists", but it's by far not the most popular category. Turning invisible could just as easily have some fantastical basis. If most of the story is elaborating on this invisibility technology and how it affects people (sexually), then it might be best in Science Fiction. It still 'fits' either way, but I think there are better choices. I would recommend either Humour & Satire or Exhibitionist & Voyeur, depending on how seriously your story takes the humiliation, and where the tone of the story lies on the spectrum between comedic and erotic. How many words are dedicated to making the reader laugh, and how many are trying to arouse them? Obviously, it's still erotica regardless, but you might want to think about what your main theme is. Based on your description, it sounds like it could go either way, so both would make good choices in my opinion.
