Opinions

It helps to know how much experience you have so one doesn't become pedantic over a point you already understood but merely overlooked, which can be frustrating for you.

Very pastoral feel in both melody and accompaniment. Coincidentally you misspelled piece as "peace" which was likely Freudian owing to the peaceful feel of the work.

The new flute melody were in you ventured to the relative minor is a good offset to what has preceded.

More interesting in terms of orchestration you ask? You've chosen 2 violins rather than a viola. Nothing wrong with that. The viola would add colors different, though subtle, than the violin, especially expressive on its C and A strings. Of course, if so choose you'd want to give it some melodic interest at some point. ('cello too.) The inner or lower voices could be expressive and would prefer to be so rather than just holding up the soprano.
Again, there is nothing wrong with twin violins. That is a color of its own.

About the harp. Nice patterns. Notice the F# in bar 38. It is normal to note the change of pedal. In the event you did not know, the pedal harp is diatonic, not chromatic. The strings are set at the opening and changes are inserted underneath the point of change.

These two ladies will explain:

http://www.jpharp.com/a-short-guide-to-the-harp
http://harpspectrum.org/harpworks/composing_for_harp/composing_for_harp…

In a short, relatively simple piece for a harpist, s/he'd look it over and enter the change herself. However, they always appreciate a composer's regard. And if you like to write for harp, know its limitations.

The piece is off to a good start.

pv