I did this and it was fun and everything, but I never made a single cent. I did grow my personal network though :) If you value learning from others, keep your job and only quit if you make at least 50 to 75% of your salary AND you see constant growth.
> using a stack such as Python/Django + HTML/CSS/JavaScript + eventually iOS
Another red flag. Technology doesn't matter and the fact that you mention this instead of business validation you should think twice before making such a commitment.
EDIT: I forgot to add that the technology part is at most 10-15% of it. The rest is boring marketing, tons of spreadsheets, Google, Google, Google, Email^n, more spreadsheets and business operations if you are lucky.