IMO, leave flash alone or you're going to spend too much time on the artistic side of things. I think you should get your hands on QBasic and learn that, then make a simple text based number guessing game. After that you could move on to graphics and maybe create a simple 2D engine. If you get bored of QBasic, then you could move on to flash, after you've learned some programming.
I remember in grade 11 I made this awesome number guessing game, complete with highscores, bonuses, and an "AI" that suggested answers.








