Is it a good idea to quit my current job before getting a job at one of the big four?

I am currently working for a small consulting company, but the position is a poor fit and I don't like what I am doing. I found out from friends that my background is very suitable to some position(s) at big fours. I have been researching on them and am getting more and more excited about it. Unfortunately, what I am doing now is not helpful regarding building up the skills and getting myself ready for those positions. It's also very tedious and leaves me little energy for preparing for the new job/job interview. I am thinking of quitting the current job so that I can focus on the preparation. I don't want to apply first before I don't want to screw up any interview opportunity in case I am not ready. My thought is to prepare well and to demonstrate to the potential employer that I have adequate knowledge and skills to do the job even though I don't have exact experience. Financially I am safe for 5-6 months. I am confident that I will be competent and I am passionate about pursuing this new career. Do you think it is a good idea to quit my current job before even getting an interview?