So in DUR the art had Damian celebrating his 13th birthday (that apparently no one including his dad cared about.) This is weird of course because DC kept making a point of saying he was ten even when Tomasi tried to age him up a year and a half. It confused me too because new 52 Damian was like five before Talia aged him up. Wally says ten years are missing so maybe that's not canon anymore.
Aging Damian up threw me because his age is supposed to inform you how much time passed and how old everyone is. Now I might be wrong but my theory is that no one else will be aged up. Otherwise Tim, new 52 Wally West (who really need a different nickname now), Steph, Jaime and all the other teens would be 19/20 now. Without aging everyone up it means Tim is now 3 years older than Damian.
Then it occurred to me, they want Damian to be a TEEN Titan. This does put a bigger gap in the ages between Jon and him. Jon is 9 so unless this was a mistake that gap might make a big difference. He might see Jon as a baby, etc.