This is really well done for a first piece. At the moment there is only few things i can think of for improvement is that this piece could benefit for more counterpoint mostly it seems one idea at a time but having multiple ideas can be highly effective for example in danse macrabe by seant seans he uses multiple melodies and at the climax he have them both at the same time is one example. This also helps add multiple layers of depth.
An other example could perhaps be krull by james horner, in the introduction he does a simliar thing you do with one idea at a time but what he does is perhaps in two clear contrasting forground elements one at a time with a background element which all are develop.
an other thing i feel like could be improved is the ending. it feels a bit sudden and dissconcted from the material. Perhaps make it more thematicall transition?
What could make the finally more smooth transition wise is maybe a suspensful build up slowly with the ideas all ready present.
I think what you did really well was communicating the overall emotional arc of the piece which can be really difficult espcally at a beginner level.
Some of the thematic elements of the piece during the middle section could be a tiny bit more memoriable. Perhaps more use of motivic ideas?
If you look at john williams scores some of his melodies like indianna jones, harry potter, schindler's list , E.T Or Darth vader theme for example have a core idea which is repetition with varity of almost one or two ideas. With this added it could perhaps be more thematical and coherent
In the intro perhaps you could add an extra layer of depth with a suspen high string effect somehow? until the brass comes in? If that works.