LOL, I've felt like this before and I'm only 21. But seriously, there's people adding me on twitter (more than LJ, since my LJ seems to attract 17+ people, don't know why) that were born in like 1997 and it's so disturbing to me! I go to classes with 94ers and it's weird enough when some of them tell me they've never done this or that (take drinking, for instance) or that they need their parents' permission for something (doubly cause my parents always let me do whatever I wanted, for the most part, so "parents' permission" isn't something I'm that used to, lol). SO IMAGINE coming to fandom and reading 12yo and 13yo reading porn and saying some of the things I've read on tumblr. They're especially young on tumblr. And I come from fandoms like BSG or Supernatural where I've mostly met people in their 20s and 30s, some even in their 40s! I was the maknae there D:

And it's sort of wrong that I'm all "OMG WHY" when I got into the Buffyverse and the Harry Potter fandom at 13 and started reading smutty stuff right away (partly cause I always clicked better with people older than me; I did a lot of things before most people my age, take reading porn, drink alcohol or even trying a cigarette which luckily I hated!, so I would obviously do this soon enough too!). But idk, it does get weirder when you grow older.

I lol'ed about the conversation with your sis. I get the feeling that my mom ~imagines that I read and have writen some sex so far. We've always been very open with this topic, and she knows me well enough to guess I wouldn't have a problem with it and would enjoy it. She's always told me she wants to read what I write "no matter what it contains", which tells me she sort of guesses a lot of what I write, lol.

Good luck with NaNo!