Clever DD and why I think it is Dudley

[hambtty]

No: HPFGUIDX 145690

When Petunia Dursley reacted so strongly to the news that in the WW 
children come of age at 17 not 18, I couldn't help but wonder why.  
Why did JKR want us to know that Petunia was shocked and remained so 
for the rest of DD's visit?  She described several physical 
observations Harry made about his aunt in that chapter that puzzled 
him.   What does it matter to her, to her family?  She should have 
been thrilled for Harry to leave a year earlier than expected.  

Then there is DD's inference that at least they didn't mistreat 
Harry as badly as Dudley. Did DD trick Petunia into taking Harry in 
by promising her or dare I say making an Unbreakable Vow?  She 
clearly thought Harry must live with them until age 18, DD knows 
muggles consider their 18th birthday as coming of age.   DD could 
have promised that Dudley would be "protected" from becoming a 
wizard until his 18th birthday as long as Harry still called their 
house home until his coming of age.  Then at 18 Dudley would lose 
his magic forever – Dudley is a month older than Harry so in 
Petunia's mind he would be 18 before Harry came of age.   If DD 
worded it just right then that would give Dudley one year to 
discover he too is a wizard. When Harry leaves will Dudley discover 
his magic?  

Then I remembered a quote from JKR hinting that someone will become 
magical at a late age.  Late age?  What could be a late age – surely 
17 is considered late in the WW.  I know most think that it will be 
Mrs. Figg but surely she would have discovered her magic, if any by 
now.  As for me, I think it is Dudley.