I think you should sync the scene transitions with the music a bit more. there is a really obvious down beat in the song, and most of the transitions happen either right before or right after it. having the scene transition on the down beat will make the animation and music much more cohesive. There were also a few blips in the music that you might want to address, for example, the music skips around 40-41 seconds. also check the timing for a few of the scenes, as the sword shining scene seemed far too long and broke the flow a bit. check out how other animations/movies treat those sorts of scenes for reference.
overall, though, not bad for a first animation! interesting in seeing what else you'll come up with in the future!