Oh right I see.

Obviously the modern vampire has existed for just over 200 years and been told in many forms in that time.

It's been too long since I've read The Vampyre to be able to recall, and I've never read Varney or Carmilla to be able to comment on those, but the idea of vampires being emotionally stunted goes back at least as far as Dracula, where van Helsing monologues at length about the vampire's "child brain"—its simple-mindedness and almost instinctive/animalistic approach to going about its plans. And obviously you're already aware of how Rice's vampires are stuck at the age they were turned. Though as I write that, I wonder how that general trend in her books meshes with the portrayal of Claudia in Interview developing sexual feelings despite having been turned as a very young child. A retcon/something Rice developed more as the series went on, perhaps?

But anyway, my point is that the idea of vampires failing to mature is certainly not new as of Twilight or even the Vampire Chronicles. It goes back basically as far as the modern concept of the vampire. As for earlier vampiric folklore...van Helsing seems to talk about it as though he's discussing existing folkloric tradition in Dracula, but Stoker's idea of what that tradition was is very...idiosyncratic. It's hard to say how much that actually represents true folkloric beliefs, how much it represents Stoker's misunderstanding of said beliefs, and how much is the character of van Helsing. Regardless, personally I view the modern (post-Polidori) vampire as being so distinct from the folklore that there's not much value in comparing the two too closely when discussing vampires more generally.