I would say anyone joining now is still early in the game. Most of the current data will still be removed with the closing of the old test satellite and customers have just started using the network. Getting in now still means getting in on the ground floor.
Nobody can give you a prediction on how fast your storage will fill up and honestly that’s probably nowhere near the most interesting question to begin with, since egress will account for the majority of your payout anyway. So it’ll likely be somewhere between within a few days and never.