Serene Indeed!
You set the mood very well, nothing sounded out of place.
I enjoyed the flute at the beginning, it was at a good volume, although it ended too abruptly, it sounded like the flute had missed a few notes (increase the release of the flute to trail off). The cello could have been slightly louder, and on the quicker notes the attack should have been quicker, it sounded electronic with each new note.
Consider bringing in a few strings towards the middle of the piece to give it a little more body. It would help the piece feel like it's building and going somewhere. I could see strings entering and playing along with the flute the 2nd time in a high octave.
My orchestral remix of Defcon Zero kind of shows what I am talking about (no self-ad intended).
Great work, you have a diverse range of emotions displayed in all of your music. That is the sign of a more experienced artist!
5/5