If you are quitting your day job you should knwo for sure that you are going to make much money with teh bitcoin because if you are not making money with bitcoins you can better find a job.
There is no assurance that you can make money in bitcoin but if you feel you have a great chance to make more money compared to your current day job then you should take the risk, besides if you succeed you will rip the fruits of your hard work and smart decision.
Yeah if you can manage to earn higher income in bitcoin in compare to your full time job then you can afford to quit your job and get full time into it, as our primary concern should be to earn more money.