Keep the job in the bank, and test run your music career in your free time. Why? Cos you say you are passionate about music, but do you know what a music career really entails? Its not just making music, but also learning to market your band, manage your fanbase, deal with producers and what not, navigate the industry, network etc. Its like a person who likes cooking and thinks they want to open a resturant, then finds out they hate dealing with customers, managing inventory, chasing suppliers, doing accounts etc and essentially hates having to run a business, when what they really loved was cooking for friends and famiky and doing acts of service (cooking) for them. To extend the example, the dream career for that person who loves cooking may in fact turn out to be something entirely unrelated to cooking like nursing or charity NGO type work, but still has the same essence of service to others.