You could, however, it is likely you will never be able to expand your business beyond family and friends. It does not cost that much to set up a payment method on an actual website. I would suggest starting your business on Etsy, as they basically give you a website and payment method for free. Obviously they take a cut, but then you can have your Instagram link to the etsy account and basically have that be your business until you are ready to invest in your own website!