A Mistake and a Question

[jonathandupont at hotmail.com]

No: HPFGUIDX 23257

Probably both been discussed before, and the mistake in particular is 
incredibly tiny and unimportant, but:-

The mistake - 
In POA21 "Hermione's Secret" Dumbledore calls H&H "two thirteen-year-
old wizards". Surely Dumbledore is wrong - Hermione is 14.

The question -
In COS13 - "And while Harry was sure he had never heard the name T. 
M. Riddle before, it still seemd to mean something to him, almost as 
though Riddle was a friend he'd had when he was very small, and half-
forgotten."
I might be missing something from earlier in the book here, but when 
would he have heard Riddle's name? His parents if they ever mentioned 
the man would have called him Voldemort or You Know Who (& 
variations). I suppose it could be similar to his prophetic dreams or 
something, or is it just another strange connection between the two 
of them?