Hey Rosalyn! I really like the first image the tonal range is really good and the impressions from the 4th image are great depicting the movements of the model, Ill be posting mine soon look out for them :p
Very nice action lines, keep practicing. Remember at the beginning lay down a fast and smooth basic construction. Once you have the basic lay out down then add on the detail. I'll be following your progress. You can see some of my life drawings on my blog.