I would be worried about the physical side of things. It has only been 12 weeks since you had surgery on your ear and they want you to make a life altering decision in 4 weeks? I am all for CI's, have just one more batch of testing before I am scheduled for mine (only one) and I was given loads of time to think things through and research, and come here asking questions.
Is there a doctor you trust? Not perhaps one that you have dealt with for ear trouble, but any knowledgeable doctor that can help guide you in making a healthy choice based on you and your history? As for the success rate, that is on a case by case basis and depends on a lot of factors. 
