I want to be the first to say, though I like your pictures, I think they need a little work and a lot of practice. Any artist worth the pencil he uses will tell you that the greatest way to success is through observation.
Take, for example, the Theresa Wanted Poster picture. The arms have no structure to them; they look boneless tenticles. Even on Oddworld, things need structure. Ask a friend to cross his/her arms for you and draw it. Or use an existing picture of Munch as your model (I do think there is a picture of him with his arms crossed) and just draw it. It may be difficult, but if you're truly serious about wanting to improve yourself (And believe me, that's one of the artist's most difficult bridges to cross) then you should be willing to observe a LOT.
You've been given a wonderful gift, Anne. I can already see that you have the arm and eyes of an artist. But there's a lot of road left until you've mastered your art. And believe me, when you get to that point, you'll feel so good about it.
Note: Hell, I'm not even there yet and I'm 18. But I did start out drawing dinosaurs, so I think I set myself back a few years...
