Why I do not think the Potters on the Black Family Tree Were James' Parents

[heidi]

Basically, if Potter-child who's blocked on the page turns out to be James, then I'll just spit, because last summer, the woman said:

James's parents were elderly, were getting on a little when he was born, which explains the only child, very pampered, had-him-late-in-life-so-he's-an-extra-treasure, as often happens, I think. They were old in wizarding terms, and they died.

No way is 40 considered old to have a baby (JKR had Mackenzie at what, 38? 39?), and 57 is very much NOT old for passing away in Muggle terms, much less wizarding, (also see: discussion on _lore's LJ. So I personally don't think they're James' parents, or she screwed up last summer. Oops, ew, maths, and all that.