I'm not an attorney and am answering based on my understanding of the LLC I owned.
Your salary would be examined. Your business assets would not.

If you were to, say, pay yourself a salary of minimum wage throughout the year, the remaining profits or losses of an LLC would still roll through to your personal income tax returns as income, anyway. The court can request those tax returns to determine your actual income.

If you claim your income is now reduced from leaving your old well paying job to venture into self-employment, this could be viewed as a form of voluntary unemployment on your part,and not be viewed as a valid reason to request a reduction in child support.

An LLC does not necessarily pay out a salary to its owner. You would have to be a corporation to do that, either a C or an S. And if you aren't a corp, the income of the company is considered yours (based on your ownership percentage) and will factor into child support.