Well you are indeed amazing, most people your age don't come close to tech, digital drawing or the like... I'd say you are actually 25-30 in heart and soul... ;) Keep that up! I wish I had a cool Nana like you, for real.

Now about the concept art, I'd like to begin, but I am not sure where :| I make drawings by hand, and I was planning on scanning/photographing them to then edit them with my computer... I lack the drawing tablet though, and I have only used Adobe SketchBook, have you heard of it?