We writers live in a strange world of fantasy. We create stories. Sometimes there is truth in them, even if it is just a grain, but in all cases (except memoirs, maybe) we were not there and have to imagine what it was or would be like. We can travel through time and space and go anywhere, be anyone, and do anything through our writing.
But in another sense, we are always going back and forward constantly just by the nature of writing. We go forward and write a story, then we have to go back and edit said story, probably multiple times. For those of us who write series, that could mean that in our new writing we my be following a character who is ten years more mature and then have to go back and do another round of editing (probably thanks to an agent or publisher) and revisit their youth. We may have to rewrite an entire scene and we have to do it consistent with that character at that time. Then we have to return to the current project and resume writing the older version of the character.
It is a never ending ebb and flow of where and when we are with our writing. Quite a challenge. As a writer, I find it fun to be able to jump back and forth and if I wrote something I didn’t like, I can change it. I can rewrite history for my characters, sometimes by changing just a few words. But while we have the power to go back and fix things and change things (and write prequels), it is going forward that is the writers greatest power and joy. What is the next project? Who will I write about this time? Going forward is the creation of new material, new adventures. Going forward is what we live for. It is why we write.