Really not bad ! I agree with Moseph too, the melody is a little overwhelmed by the others instruments during the first minute. Otherwise, it is a pretty good arrangement and so the mixing.
You may want to play a little bit with the audio panning. For instance, the trumpet at 1:26 could pass from right to left at each "phrase", like they were responding to each other. But that's maybe just me who likes to play with panning
In any case.. Well done ! (my english may be bad too by the way ^^).