Working Capitol

As I get closer to my nightmare…oops did I say that? My dream of opening my own shop. I am constantly tormented by this one question. "How much cash do I need to have in the bank when I open? I really need to pay myself 1800 a month to live. I am planing on working open to close daily for sometime. I’m looking at a break even for a carryout/ delivery store of about 3000 a week .That number includes my wages ofn 1800. I did a cashflow projection based on doing $1050 in sales the first full week of operation then raising sales $105 each week i found i would go sideways about 13k before I got to break even. My thought was that I need to have 20k in the bank when the doors open. Plus my becoming inventory already paid. 15K doorhangers also in stock. Any thoughts?