I suspect billions of years at minimum. All of our reddit posts, and all of posts online will be used countless times in the future to create many different versions of us.

The birth of the internet is a massive influx in data, which means historically it's the first time a huge amount of data is available for earth simulations with a very large amount of historically accurate people and interactions.

The chance that you are the original you, rather than a copy reverse engineered from your posting history is essentially zero.

The answer to your question of course depends on weather or not you consider all of those different versions of you, running on all of those different simulations, to be you. What I do know is that the idea of a definitive edge to self, either as defined spatial temporally or conceptually by defining self as a specific set of patterns is an illusion used to simplify reality and bring it in to a workable conceptual model.

tldr: You merely adopted the singularity reddit. I was born in it. Molded by it.