It gets off to a bit of a rocky start, but I like where it's going. Once you flesh out the orchestration, I think it'll be more impressive.
On that note however: this is where midi hurt more than helps. It lies; it makes volumes equal across the board when this is not true. When you're doubling your winds, you want your flute above the oboe. Flute on the staff is very dark and velvety, but soft; it'll be buried by the oboe. When you're filling out chords, you want the flute or violin to be playing the soprano for projection. When you double the flute and oboe, you might try splitting them into octaves instead of unison.
Musically, you have some very nice material. You set up a lot of really good antecedents, but then don't answer them. One suggestion: at the end, when you state the theme in an orchestral voice, try echoing the statement again in another voice (oboe then violins) to give it more shape and a little contrast.
Definitely a good start. You have your melodic and harmonic structures in place, now it's about fleshing the orchestration out. I really want to hear it when it's finished.