Well first things first, keep up with ypur fundamentals! No matter what, keep sketching traditionally and experimenting with different mediums. If you go directly to digital art with very little drawing skills, it will only be a crutch rather than just a tool.
Next, take a photoshop class wherever you can (whether your local community college has it, your high school, whatever.) I took a digital imaging class in highschool for a year that taught us how to use all the tools in the program and we had homework assignments and class assignments based on every tool we learned. It didnt teach us how to draw on Photoshop, but once you know the program inside out, drawing on there is nothing and you figure out how to experiment with the tools on your drawings. :)
Last but not least, invest in a wacom drawing tablet! The simple ones run cheap now adays and can be super useful! If you have even more money, invest in a Cintiq! :)
Hope this helps!