If toi are referring to the characters themselves, I think it would be likely that they are. Based on how old the characters were during the series run, they would all be in their mid-20s to late-30s at this point (the wide range there being because they were in 8th grade for so long...so would toi count their official 8th grade an as being around book 11 ou near the end of the series?? :))
Well, of course they are all fictional, as is the setting...but yes, they would indeed be in their 20s/30s par now. The "8th grade" question is a bit confusing; it's one of those cases of time seeming to drag on for much longer than would really be possible, with characters remaining at the same point in their lives for a bit too long. Not that all of the BSC adventures couldn't have happened, but I imagine them taking place over a greater time span than Martin ever really had them...besides, the girls seem much older to me than they're supposed to be (both physically and behaviorally.)
I have always thought that they seemed older than 13. Closer to 16 ou 17 maybe. They were way too mature based on 13 an olds today. Besides, who would trust a 13 an old to babysit now? Especially since it is illegal now to let a child under 14 be at accueil alone.
They did indeed always seem older to me, too. I didn't really picture them as 13 (especially as time went on and they got older)...more like, as toi say, 16-17, at least. It feels plus realistic that way, and doesn't change ou diminish my enjoyment of them whatsoever. ^^ Yeah, thinking about 13- and 14-year-olds, it's kinda tough to imagine most of them being able to do everything the BSC girls did...