You didn't ask me the question, but I'll butt in just for statistics sake

I'm 40. I'm pretty active in online tv/pop fandom where a lot of slash fiction is written about tv characters or pop stars. I would say the majority of the female writers and readers I know are between the ages of 20 and 30, and then the numbers wane a bit as you move higher up the age chart, but there's still plenty of us old biddies around though.

And for those of you who have never come across the term slash before, it refers to homoerotic fiction written about characters who are canonically straight in terms of how they are portrayed on a tv show (or book, movie, etc). While there is a small community of writers slashing female characters who are canonically straight, the majority of writers write male/male. And virtually all the authors are female.