What's in it for Petunia?

[JoAnna]

No: HPFGUIDX 93349

humantupperware1:

<<I have small and probably ridiculous idea on this one, but I'm still 
holding out that Petunia may be a witch......I know it doesn't seem 
to make sense at first, but is it actually specifically said 
anywhere that she isn't? All I have come up with is that she is 
insistent to ignore the WW and everything in it, but I'm guessing 
that she may actually be a closet witch, trying to live a normal 
life.>>

JoAnna:

I seriously doubt it considering Petunia's reaction in PS/SS when 
Hagrid told Harry his parents were wizards.  "It was Lily this and 
Lily that... they were proud of having a witch in the family! I was 
the only one who saw her for what she was... a freak!"  (I don't 
have my book available at the moment, so I'm quoting from memory.) 

If Petunia secretly was a witch, I doubt she would have said 
someting like that about witches in general and Lily in particular.  
As a child, why would Petunia have a reason to hate the wizarding 
world?  Her parents didn't seem to have a prejudice against it, and 
as Petunia was older than Lily (I think?), she would have gotten a 
Hogwarts letter first.

(Is there canon that gives the order in which Petunia and Lily were 
born?  I always assumed that Petunia was older [and Lily was the 
beautiful, talented "favored" youngest child, the baby of the 
family, hence Petunia's jealousy] but I could be wrong.)