I read many of the earlier books even though at the time I was also already reading YA fiction, and some adult nonfiction by age eleven. I had tested at a higher reading level in school, as well. However, I saw these books at the library, and could read each one in a hour and a half or less. I liked the idea of girls being friends and organizing their babysitting together. (I just had no idea it would become a series of well over a hundred books that would eventually be ghost-written after a while. Ann M. Martin did not write all of them.)
Anyway, if the girls hadn’t been stuck in 8th Grade for thirteen or more years, they would be turning 40 this year! They should have well-established lives. I am curious. I have found some fan fiction online, but some of it is just plain weird (and rather badly written.) Some of those people have answers for what happened to the characters. I have liked none of those stories, really.
According to this link http://www.buzzfeed.com/expresident/facts-about-the-baby-sitters-club-that-will-blow, Ann M. Martin had somewhat vague things to say about where the BSC girls would be now. It doesn’t tell us if they got married, had children, specific careers, etc.
Here is in interesting (and more detailed) take on where the characters would be now: http://thehairpin.com/2011/01/the-baby-sitters-club-where-are-they-now/