Because comics are an ongoing medium, there's no way to craft the timeline based on actual years. If Batman first put on his cowl in 1940, then he's 95 years old today. No matter how often the timeline is reset, the characters will always age uncontrollably if you try to use actual dates. Instead, the timeline will be structured around a 'number of years ago' system. Batman first donned his cowl fifteen years ago. This is true if the comic in question is being written in 2012 or 2018. With this method, the characters CAN age forward in a controlled manner, but still remain at an age we all collectively understand.
All that said: here's our reconfigured and re-imagined DC Timeline.