The way time travel in Kingdom Hearts works can be described by something called the Predestination paradox.
A Predestination paradox occurs when the actions of a person traveling back in time ultimately causes the event he is trying to prevent to occur.
So maybe it isn't exactly like that in KH, but think about it. One of the rules of MX's time travel is that the time traveler can not change things that are destined to happen. Basically, MX goes back in time, talks to his younger self who then sets up the events of the series. There is no "before" because that time travel is set by an infinite loop. That's how time travel is possible without events being changed.
The way time travel in Kingdom Hearts works can be described by something called the Predestination paradox.
So maybe it isn't exactly like that in KH, but think about it. One of the rules of MX's time travel is that the time traveler can not change things that are destined to happen. Basically, MX goes back in time, talks to his younger self who then sets up the events of the series. There is no "before" because that time travel is set by an infinite loop. That's how time travel is possible without events being changed.
I just confused you even more didn't I?