We flat-out don't understand what time is, whether past and future are realities or just illusions, what the present might be other than an infinitesimal between two illusions.  We also don't understand why it seems to have a direction forward (maybe it really does) when at the atomic level all events can go either forward or backward in time.

I think therefore it is a bit foolish to make statements like stuff has to exist for there to be time and that time is generated by events, although that seem the common-sense view.  Time is also one of the aspects of the "thing" called space-time, and flows at differing rates according to frame of reference -- stuff that works fine mathematically but the human mind is not built for and takes a good deal of thought to conceptualize.