The third is my favourite - nice mood and great sky. The lighting in the first one is superb, and I love the mountains; not too sure about the clouds, though. Some of them hang very low, which looks a bit unusual. I don't quite like the second one, although you have a rather impressive mountain range there (which I usually like). But I guess it's the sun's angle which makes the whole image a bit flat as there is hardly any shadow.
I must say, for one week's experience that's a very nice start. Keep those images coming!