nickhopkinsjnr,
Definitely a step (or two) too far. You seem to have done all the right things so do not worry.
I went to my stage 3 with a lot of information and knowledge that was never used.... I read Graham Duke's book a few times plus "Air Band Radio Handbook" and "International Air Band Radio Handbook". Reading them helped me get a better understanding of ATC (and it increased my confidence for the interview) but, if I think of my interview, all the questions could have been answered without reading them. My visits to TWRs and ACCs had more relevance during the interview.
I personally think stage 3 is not an exam about ATC knowledge, they do want to see some ATC knowledge but they also want to see genuine interest, motivation, how you think, how you justify your decisions, ...
Bear in mind that stage 3 is the first time they can get a bit of an idea of your personality face to face (the structured interview in stage 2 is not used for that)... and getting through college is not exclusively about previous knowledge but about personality, work ethic...
Good luck
