hey! nice work there mate! im around your age (plus a few of years) and i'm reasonably new here too! (mabye 3/4 months) if you check my sketchbook, and others you will see that no one really gets many replys strait away, so i thought i would come and give some encouragement. all you have to do is post as much stuff as possible and people will see it, if they like what they see, they'll come back for more and mabye even give some tips! so far i have found everyone to be really helpful.
anyway, your stuff looks pretty decent, the akon one is good except that his mouth is a little lop sided.
good to see that you are mixing your media already, took me years to even try it haha.