congratulations on finishing your first original song! Your lyrics writing and vocaloid usage has improved a lot, and I'm happy to see you moving on to original work!
I'm not very good with music theory lingo so I'm not sure how quite to word my constructive criticism, but if I may offer some suggestions- The instrumental is kind of bare bones, which isn't necessarily a bad thing, but I feel like the guitar lacks a good, strong rhythm. I think if the guitar had a catchier rhythm throughout the song, it would help. Perhaps someone who is better with musical terminology can offer some more in depth advice, sorry I'm not too helpful!