Hey, this rendering is pretty good for a 15 year old artist! And I'm interested in your gravity mage idea.
Just a little opinion; maybe you can change the colour of the those wing-like hair bands in her hair? Right now it looks like they're connected to her head because they're the same colour. Maybe yellow/gold to compliment the purple in her clothes. (If you want, you don't HAVE to do this. Just my opinion.)
Good luck with your character design. ^^