Use the try harder Luke.

What do you mean by "not new to programming at all"? How many hours programming have you done? How many projects have you completed? Because unless you've had a job as a programmer before or you did CS as a college degree your previous experience will be utterly swamped by App Academy. If you feel insecure about algorithms specifically practice them specifically. If you want more practice with Ruby maybe do Hartl's book. The Codecademy Ruby course is not the end of the world. If programming appeals to you prepare, apply and let App academy do the judging.

Edit: Remember, many people who have had jobs as programmers can't do FizzBuzz if asked to in an interview. Retain hope.