Determining when the present occurs in a fictional world is another choice that worldbuilders will need to confront early in the design process. While some worlds do not need a ‘present,’ and many worlds will span many epochs, worlds built for a specific narrative should consider the period in which that story takes place.
When making decisions about the age of your world, it can be helpful to place this within the context of real-world history. This can be done despite differences in the societal development of your fictional world and the real world. Thus, a fictional world may take place in a medievalesque time-period (as many fantasy worlds do), our future (as many sci-fi worlds do), or a Victorian age (as many steampunk worlds do). This can be the case despite a fictional world, say, not actually having a Queen Victoria. Deciding on a current or dominant era simply provides a framework onto which era-appropriate elements can be added. The era determines if someone will use a rifle or a sling and, in this manner, makes it easier on the worldbuilder to decide what elements to include or exclude immediately. Once a dominant period has been established, alterations can then easily be made, such as advancing the adoption of specific technologies or eliminating them completely instead.
Just because a world has a present, does not mean that present exists independently from that worlds’ internal timeline. Considering the sequence of events that produced the current era is critical for worldbuilding. Eras and events preceding the current narrative will have an impact and many worldbuilders generate a timeline to help them keep organized.