Much to be admired about this piece. If you would humour me, strive for a little more contrast. I think my interest waned a little with the lack of development of the rhythm in the motif. Maybe, if I was sitting beside you, I might suggest that you "double" the length of the motif sometimes, extending the sweep and wave of the melody, and enriching it with some rhythmic undercurrents and harmonic spice. These strategies would "unbalance" the piece more, having impact like an artist "breaking the frame", and this would raise the mystery quotient of the melody. But, it is a good "first prelude". Well done.
