Rowling teased a group of fans with morsels of information as she gave a public reading of "Harry Potter and the Order of the Phoenix" at the Edinburgh International Book Festival in the Scottish capital.
"He will survive to book seven, mainly because I don't want to be strangled by you lot, but I don't want to say whether he grows any older than that," Rowling told the youngsters.
She encouraged the fans to try to piece together future plots for themselves, and urged them to focus on why Harry's nemesis, the evil warlock Voldemort, had not been killed.
"There are two questions I don't think I've ever been asked and that I should have been asked, if you know what I mean," Rowling said.
She told the gathering they should be asking themselves "not `why did Harry live' but `why didn't Voldemort die?"'
The second question they should think about is: "Why didn't Dumbledore kill, or try to kill, Voldemort?" she added, referring to the headmaster of Hogwarts School of Witchcraft and Wizardry.
More than 500 people had tickets to see the author read from the fifth book. She is still working on the sixth book, but has already revealed the title: "Harry Potter and the Half Blood Prince."
But she remained tightlipped about the title of her final book in the series.
"I'm not going to tell you, I'm sorry. The trouble I would be in if I did. My agent would have me hunted down and killed," she said.
Rowling further teased her fans over whether Harry's pals Ron Weasley and Hermione Granger would be boyfriend and girlfriend by the end of the series.
"I'm not going to say. I can't say. I think I've given quite a lot of clues by now on this subject," she said. "You are going to have to read between the lines on that one."