BGS in 5 months
It is absolutely possible to get it all done in 5 months, I started at the beginning of December 2006 and got the last exam completed 3rd May 2007. I used to drop my son at school at 9am and start studying, finishing at 3pm to pick my son up and then studying from about 7pm until 10pm every evening Monday - Friday. I also used to study weekend evenings. I managed to pass all exams at the first attempt with a 93% average which is more a testament to the quality of the notes and the instruction during the brush up courses.
I did have some aviation experience before starting the course having completed 22 years as an avionics technician in the military. But by no means did I know an awful lot and I am not at all academic and being 40 years old when I started the course then age was not on my side.
I cannot recommend the course enough the notes and the instructors are superb. I sincerely wish you all the best with whatever you decide to do but the whole lot in 5 months is there for the taking.