This big question with time travel is what sort of a music player is life.
Is life the sort of music player wherein once you start a playlist in shuffle mode the music player shuffles the tracks internally and you can go back and fro among tracks and the same pre-shuffled order is maintained (i.e. the playlist appears random, but it’s not really random because the randomness is introduced just at that starting moment; so if you were to build a time machine and go back in time you can’t really change anything because you follow that set path, everything is kind of pre-determined).
Or is life the sort of music player wherein once you start a playlist in shuffle mode the music player always chooses the next track to be played only when the current track reaches an end, and while you can go back to the previously played tracks (i.e. you can build a time machine and go back to past events) but once you go back to a previously played track, the next track in the list is a new randomly chosen track (i.e. once you go back in time you can change the future; things aren’t pre-determined, there is no set path).