Short and sweet
Not a bad effort for a first try, but a few things to improve on...
Nice use of music throughout, which did a lot to add to the mood of the animation. In future maybe check out the audio portal here on Newgrounds for a wealth of music to include in your animations.
A nice short tale that wasn't overcomplicated and was reasonably well paced (though a bit slow to start).
Decent if unspectacular drawing, though I did feel a touch inconsistent. Some of the drawings at the start were worse than those at the end, suggesting that you were improving all the time (a good thing!), but could have gone back and reworked the beginning a little.
Animation was minimal (though the use of a skateboard to prevent your character simply floating along the ground was inspired). Maybe try and be a bit more ambitious with animation and get a few more moving objects into each scene- nothing too radical, one step at a time, but I felt you actively avoided animating objects here rather than giving it a go.
Sound effects were a mixed bag- making your own with a mic might have been a better option (the scream especially was grating).
Definitely worth a pass though, good work and keep improving.