So far it seems pretty nice. First off, the intro seems to take a bit long to build up into the main song IMO. At about 1 min, there is a rough transition that could possibly be fixed by some percussion filling in the break you did. the soft section at 1:25 or so is a nice touch, but feels odd at first coming immediately after that previous part. Maybe there's a way to take a little bit out slowly to have the same effect, but not as rough as a transition.
I think overall, I would like to have heard a prominent melody in there. There is a melody, but it seems to want to blend in with the harmonies. It might be nice to break free a little more. At 3:45 the drums fall out of rhythm and it feels very out of place. You might want to change those up.
Ending was really abrupt.
A very relaxing feel, and definitely not bad for your first submission. I think the biggest thing would be the melody needing to become more prominent at least in some portions of the song, as it just blends in and while that is a nice relaxing feel, it should change that feel at least for a portion, so we don't get bored as listeners.
Keep up the good work.
Mixing overall is a little quiet, but that is my only issue. I think just a punch in overall volume would fix that.