To give you an accurate opinion on the form it would be nice to see the score. Anyway, since the piece is constructed on a repetition of a phrase, there is no complex structure here.
Apart from the ending, perhaps, as a coda, from 4:00, the phrase repeats on and on in a sort of A1 A2 A3 A4, etc... What happens is that every exposition changes by means of the orchestration, or the chorus, or the sopran voice, or the rhythm.
The arrangement is good, for me, I like it. Yes, of course it is repetitive. For the time it takes it's not boring, but .... almost.
I think this work would improve a lot if you write a second theme, different and contrasting, just to build a basic ABA form.
I always say that studying the classic Forms is easy and funny, and it allows us to make better pieces. For example, a modulation here would have been an interesting change, too.