@Aaron Liu,
Don't Quit the part time job!!! You need and will continue to need the income its currently generating for you right now. Think about what you just told us, your JOB is your ONLY monthly cash flow.
Your REI cash flow has to be enough to replace the cash flow from your job plus it has to be enough to pay your REI expenses, your personal expenses, provide some extra cushion for other monthly expenses and emergencies and it also has to be enough for you to comfortably sleep at night without being worried about lack of money.
Believe me the 6 months emergency fund is not enough for you to live on (rent, food, etc and pay all other expenses). One year emergency fund might still not be enough. I found out the hard way and I am still licking my wounds.
Having that job is an advantage at this time for you, because you can also use it to borrow if needed. It is security for you right now. Since you are in IT maybe you can ask your employer for an opportunity to work from home, even if it's a couple days a week.
At the end of the day, the final decision has to be your own. Think about it v. carefully and put your plan in writing, the pros and the cons. Your dream will become your reality, but do not forget that you still need to live in the present.
All the best to you.
@Aaron Liu