Another source of information will be the bills and receipts that you have received over the past quarter. If you have not kept such documents and records before, then now is a good time to start. The good organisation of your important financial documents, and orderly filing of bills and receipts, will stand you in good stead for controlling the family budget when it is set.
This will show your Angel Investor that you indeed are a rational thinker and concerned about the money as well as the truth. If the Angel Investor cannot trust you your chances of being funded are nil. An angel investor is betting on the jockey not only the horse. As an entrepreneur you must be honest with yourself as well as your financial partner. They want to make sure you believe in what you are doing and that you also have risked your own capital, time and energies into the new business. Angel investors want you to succeed and often they also like to give their input and if you end up taking their money for your startup, the need to realize that their input needs to be taken seriously.