Thoreau and Walden Pond, depicted by NC WyethMy understanding is that we began (pre-mortal) life as spirits, each of whom can trace their origin eternally; at some point we became sons and daughters of God (that is, of Heavenly Parents); and at some later point we were incarnated when these spirits took-on bodies.
Thus, (with a few exceptions, probably) I believe that this is our one-and-only incarnate mortal life.
(To complete the sketch: when we die the spirit is severed from the body; and then we are resurrected with immortal bodies.)
I explain the typical experiences and memories that are usually taken as pointing towards reincarnation with previous earthly lives; as being actual occurrences of our pre-mortal spiritual existence - when we were a type of 'angel', each of us engaged in some distinctive way with work in God's creation.
So, when we have a sense that we really were present at some time and place in earth's history (for example) it is possible that we really were there, as pre-mortal spirits. We were not a specific historical person, but may have been present and intimately-involved with the divine destiny related to some people, some era, some location...
This may well explain my own very solid and long-term fascination and empathy for a few very specific places, times and persons; for which I seem to have memories of a spiritual, aspirational 'atmospheric' nature - but no solid, specific physical details.
Three examples are the English Lake District (specifically around Keswick) at the time of the Lake Poets such as Coleridge, Southey and Wordsworth; Concord, Massachusetts at the time of Emerson, Thoreau, Alcott; and Oxford at the time of The Inklings (especially Tolkien and the Lewis brothers).
Just to clarify, I do not feel any special identification with any of these individuals; but I do feel a strong identification with their core spiritual-intellectual aspirations and efforts.
Taken together, all of these make an obvious theme of romanticism, of escaping 'modern' alienation and breaking from materialism into a (mythic) spiritual awareness.
Despite the fact that this theme goes back to my middle teenage years, long before I was a Christian, and long before I could articulate this theme (which has, indeed, happened only with the past few years) - this is, and always has been, my most deeply-cherished theme and hope. And becoming aware of it - explicitly, and in a coherent fashion - is extremely encouraging, energising and orientating.
Of course, it is possible to write-off this notion as a wish-fulfilment fantasy, because it is based upon subjective conviction. About this I have nothing to say: I merely state my own understanding. The value is personal - my understanding of my situation is not necessarily or any interest or relevance to other people, especially strangers.
But you may yourself have a different set of fascinations, which may yield a different impression of pre-mortal concerns; and this may lead-onto a clarity about your business here-and-now, in this mortal life - the essence of what you, personally, are 'here-for'.