Something I've been working on inspired by the poem, not finished
https://flat.io/score/5a846a8f98fbfd77be4a1dd6-nothing-gold-can-stay
If you want to use a more intricate music notation website, I use Noteflight. You can use many instruments, you can set dynamics, you can add other markings to the music, and it's been around for over 10 years at this point.
Also, the melody's good, but the bass part feels plastered on instead of mixed in with the melody. Keep working hard though! :D