Hi there, @MinGry, welcome to the Forum!
This is a decent piece of music, for a start, although, I do realize there a lot of compositional errors too.
Bars 1-2: One of my favourite parts. It kind of has a nice, catholic tone to it.
I would say, this quiet opening really fits my style. Appreciate that, though stop writing tempo numberic markings, and start using muiscal terms more. (eg. Allegro; Fast, or Largo; Slow, etc.)
Bars 2-4:
This is where things start to get messy.
you have a clear sense of 'adequate rhythm'. The problem with the piano's entrance is how it just sits there like the ending of the second movement in Haydn's 34th Sonata. You have a plain, split-up C7th Chord. Not interesting. This is the entrance of the piano! Not at all. It feels like some kind of bystander, doesn't it? (for reference of the chord type reference, go to 9:53, https://www.youtube.com/watch?v=Db-XgC7tUqM) And, also, there is a lack of pattern. There is at the first beat there, and then you lose it. It becomes a mess. One of the key principles of composition as I have learnt from my teacher was opposite movement and balance. Here, you are just moving one way. Up. (Until the last beat, but, yeah, just talking about the majority here...). That part can be rethought, can't it?
Bar 5:
you have a good idea here. Decent, to the least. the piano plays a memorable sequence. You got my recognition here. Piano plays a great accompaniment alongside a melody. Wait?! Melody! I forgot that!
Anyways, the melody is a single note of a strict f? No literally, the tonic is just sticking there like, I don't know, some person that stands in the rain for hours. Kind of, I don't know. Interesting.
But I see what you you wanted to embrace there. You wanted to tell us, 'Guys! This is the start of something big!'
Sadly, though, you could have done that in other ways too, other than saying 'F!'
(not done yet, gonna come back later)