http://anima241.deviantart.com/gallery/Not bad for just a kid, but I'm not particularly impressed. I'd certainly expect a lot more of anyone who calls themselves any kind of artist, even if they're only 17.
With that said, don't be afraid to post your work here regularly. This isn't a place where people post a lot of critiques or attempt to show each other up, so it's a pretty laid-back atmosphere. Consider it a good place to show off all of your practice work and get some appreciation for it, but an awful place to try and get a decent critique or some help improving. Also, consider buying a Wacom tablet. Even the small ones are pretty handy.
Anyway, welcome to the Compendium.
Also, change your sig. It's too damn big.