Then do you think that after a simple text game I should make Pong? I'm planning on delaying 3D as much as possible and concentrate on (game) programming solutions / logic, and 2D.

How much math-like stuff is normal for a game like Pong? From the top of my head I'm thinking of: scores; registering and positioning the ball; letting the ball bounce properly; registering and positioning the two moving players; general confinement in a constant playing field.