Age shouldn't be a factor guys on the criticism given if it is good criticism. You guys no doubt want to get better (like everyone) and so really any advice should be welcome if its good advice.
Your melodies in general are good, however, it feels like there are few flubbed notes here and there - timing issues and maybe one or two wrong notes. If you are recording in with a midi keyboard or something dont be too satisfied with your first 'goodish' attempt but rather use that as a template to get something tight sounding.
I agree with Manducator that the loudness of the song is actually bringing down the effect its elements have. And some of my songs are stupid loud too.
Both those things said, your melodic sense and structure sense are good (aside from what I already said

).