I watched TDK again yesterday after along time. Its hard to tell how old Gordon's daughter was. But with the time jump to TDKR and another for a potental sequel Barabra would be about the same age as Robin.
Its clear one of the reasons they had such a huge time jump was so that Robin would have been very young when Batman debuted. Beyond the comic tadition of the age gap. But to show the inspiration Batman gave. Whch would have needed to have been a kid. Watching the first two movies now, its easy to imagine that little "John Blake" is following the Batman's exploits in the news. Talking to other kids about him.
Its fitting that Gordon Joseph Levitt was a child actor so we know exactly what he looked like younger. Also that Bale himself started as a child actor.
Anyone notice that the current issue of GQ kind of gives away a huge spoiler?
Levitt is on the cover with a large caption
"BOY WONDER - GORDON JOSEPH LEVITT"