The Batman timeline that I devised is unofficial. That is, this timeline is created from my own personal observations and research. In order to make sure that this timeline maintains it consistency and validity, I had to incorporate many assumptions and constraints.
An assumption is easy enough to understand. I take a vague statement and add my own thoughts on what that means. For example, in "Artifacts," Nightwing states he was using the name for a decade. Since the year was stated to be 2027, we can assume that he became Nightwing in 2017.
A constraint is something, in this case fact, that is binding and can not be modified. For example, in several episodes over the years, Batman is explicitly stated to be eight years old when his parents are murdered. This fact is a constraint, and is used to calculate years in which he was born or other events such as the first year Bruce Wayne was Batman.
With that said, here is the Timeline.