Whatever state licensing or registration requirements you might have, don't affect your federal taxes. You have a business if you engage in work with the intent to make a profit, regardless of what kind of registration or license you have one when you get it.
Now, if you intend to make yourself an LLC, or an S Corp. or a C Corp., then you will have some very different tax rules then if you are a sole proprietor ship on schedule C. But that still doesn't change the fact that if you have start up costs in a tax year before the first year when you have income, you can expense or amortize the start up costs beginning when you actually have income.
