Hey Draconia, I really don't think you need to worry about composition right now but since your asking here's what stands out to me. You did a good job for what the assignment was asking for though (photobashing the images)
1) the mountain on the right has a lower perspective to the rest of the scene.
2) same with the house.
3) the colors are all over the place - in the back you have icy mountains with a really bright sky right above it. in the front the piece seems to have a warmer feeling even though the sun seems to be blocked by some clouds.
again i would recomend you ignore the feedback though. I believe the point of this exercise was to get comfortable with different tools in photoshop.
hope this helps.