Well, I mean you have to do whatever makes you happy, Susan. Is this something you've always wanted to do? Do you have an experience with restaurants? I'm just asking because I want to help you make the right decision, not because I think it's a bad idea or anything! But if you really really want to do this, try it! I can help you if you need it. Maybe not with money, but with other things, sure!
What about Gringott's? You could ask for money from them maybe then pay it back?