When do you become a "business?"

[Lolo76]

I was going to do a search for this topic, but the keywords will bring up too much junk - so I'll go ahead and ask!

I am breeding my first pair of BPs right now, and might breed another girl later in the season. When I go to sell these babies, should I already have established a business name for myself? I'm not talking about anything official/registered... just a name, website domain, etc. I'd like to look as professional as possible, but also wouldn't want to appear more important than I am. So when did you officially become a business, and not simply Jane Smith selling a clutch?