Does something that is fixed go on forever?

Does something that is fixed go on forever?
Does something that changes go on forever?
Does the universe change or is it fixed?
Does it have to be one or the other?
Can everything (past, present, future) just be? In other words can it be all at once? If it is all at once, is it fixed, or is it ever changing?
Is it both?
If it is ever changing, then how can the past, present, or future be fixed or all at once?
If it is not ever changing, then how can the universe be infinite, without beginning or end.