I think it sounds like a great deal of fun!
However, as I watch businesses around me open and then close within a few months, I often wonder if folks realize when they start out that the rule of thumb is to have enough capital to see you through at least a year...because it's supposed to be a year before you begin to break even...much longer to start turning a profit.
So...I'd definitely get some expert advice. I'm sure that inventory for a yarn shop is quite expensive, and you'd have to front that.
That's pretty much the extent of my knowledge...I know there are small business loans and such, but they may be hard to get just now...definitely research it thoroughly before jumping in!
But once you do, if it looks feasible, then I'd say go for it! Just make sure your expectations are realistic.