Fragment of the first part Op.7 Symphony №2 - Rebirth (need advice)

Hi! I’ve set myself an ambitious goal: to compose a symphony dedicated to my beloved late teacher. Even though I’m not from the music world at all and have no formal musical education, I decided that it’s going to be a large five-movement symphony, with massive outer movements and a choir in the finale. I’ve already started composing the first movement, but in the last few days I’ve felt that something is going wrong. I really want to hear an outside perspective to tell me whether my thinking is on the right track. It feels like I haven’t even finished the exposition yet, but the quality of the writing is already starting to drop and the form is falling apart. Starting around 4:37 I feel like I get carried away in the wrong direction, and maybe I should rewrite that part. I’d be very grateful if you could either dispel or confirm these worries.