I understand where you're coming from. It's clearly amateur, but that doesn't make it bad. It feels like watching the end credits to an anime I haven't watched. The artstyle is cohesive, and nothing seems out of place.
You likely learned a lot during the process of making it, and so your skills and vision now far exceed where they were when you started. That's the artist's curse!
If you were to change just one thing, it could be the opening shot of the tree, which doesn't have much to look at and goes on a bit long.
Pat yourself on the back for finishing an animation project! Take what you've learned and put it into the next project!
Look for royalty-free music if you're not up to making it yourself or getting someone else to do it for you.