James's age

[justcarol67]

No: HPFGUIDX 173136

Did anyone besides me notice that James Potter is referred to in OoP
as being fifteen, the same age as Harry, in SWM, but that all of the
characters whose ages we know would actually have been sixteen in that
scene? James and Remus were born in March; Severus and Lily in
January. none of them has a summer birthday like Harry. (Snape says
that Sirius was sixteen at the time of the so-called Prank, which
seems to have occurred shortly before the worst memory, and he has a
75% chance of being right since unless Sirius had a summer birthday,
he, too, would have been sixteen.) 

So JKR seems to know that Sirius and Severus were sixteen, but she has
the adult Black and Lupin refer to James as fifteen at the time. How
could they misremember James's birthday? Are they trying to excuse him
by making him seem younger than he was, or is JKR herself just
thinking of Year 5 as age fifteen? She says somewhere that Hogwarts
students take their OWLS at age fifteen, but three-quarters of the
students would actually be sixteen. Or maybe she hadn't given him a
birthday yet and was thinking of him as being the same age as Harry. 
It could have something to do with having a July 31 birthday herself,
I suppose, and forgetting that Harry is younger than most of the
students in his year. (In PoA, she has Dumbledore, who, of course,
couldnt be expected to keep track of students' birthdays, refer to
Harry and Hermione as "two thirteen-year-old wizards," but Hermione
has been fourteen since September, about eight or nine months.

Oh, dear, maths!

I don't suppose it matters, but it's a continuity error. I suppose she
should change James's birthdate in DH if she wants to correct it. The
part where Harry says indignantly, "I'm fifteen!" won't work if she
changes James's age in the scene to match the age on his tombstone.

Carol, sorry to post on such a minor point but I was afraid it would
count as a spoiler on OT Chatter