This is an area of interest for me, though to be honest, I really don't care much for the New 52 or Rebirth.
If we were to talk about New Earth, however...
According to official info, the first Crisis took place 6 years into the careers of Superman, Batman, etc. Zero Hour was Year 10. Infinite Crisis is supposed to be about year 13, which would make Final Crisis/Blackest Night/Flashpoint about Year 14.
Superman and Batman I think were both supposed to be around 25 during Superman: Secret Origins and Batman: Year One. Assuming Wonder Woman, GL, and everyone were around the same age, this would make them around 39 at the end.
I'm pretty sure Dick Grayson's age when he became Robin has been fairly fluid over the years. I'd be very interested in getting info on him and other OG-Titans-age characters, as well as the second-gen-sidekicks like Tim, Cassie, and Conner.