First of all, I'll just be frank and say that mastering probably wouldn't have done a lot to help this track, given that it's a pretty stale piece with only a few different sounds playing. The delay whistles were cool enough, and I can sort of sense a space theme to it, but I think they were a little too piercing on the high ends. Everything else was pretty lackluster, for the most part. I can't be to critical, because you it still feels like you're trying to look for your sound, so I'll try have to address everything else a bit broadly.
The synth lead that you had going on was acting a little circus-like. There just wasn't much flow to the beat, and I don't think it was really in tune with a key. The beat itself was also quite random given that the synth sounded like it wasn't really following it in any particular way. I would look into common rythms and basic music theory to get an idea of how you can construct a smooth track without making it sound like it's going all over the place.
For your first composition ever, it ain't half bad. It just needs a to have a foundation to get the ball rolling. And maybe some additional instruments would help? In electronic genres, people can get bored of listening to the same thing being played pretty quickly. And whether you want to make this into a full track is entirely up to you.