Exactly what will you do as a "loan signing agent"? It is important to understand the limits of what LLC (or corporation or other limited liability entity) would provide you in terms of liability protection. As a sole proprietor of a business you are personally liable for all debts of the business, even those that arise simply because you are the owner and not because of any fault on your part, e.g. damages done by the negligence of your employees, etc.
A LLC, on the other hand, protects you from liability for those debts that you would otherwise owe just from being the owner of the business. Thus, you are always personally liable for your own negligence. So it's good that you have the E&O insurance and you should ensure that you have any other kind of insurance necessary based on the details of how you plan to operate.
The LLC does protect you from personal liability for contract obligations of the LLC so long as you don't personally guarantee those contracts. Experienced lenders and other businesses will, however, insist on your personal guarantee of loans and other significant contracts when the business is a single member LLC that has few assets and provides personal services since the LLC itself would provide little security for the contracts.
Also note that as the single member of the LLC there are some things, like certain taxes of the LLC, that you would be personally liable for by statute. Also note that a single member LLC is treated as a sole proprietorship for both federal and Colorado income tax purposes. So there is no tax savings here one way or the other.
So depending on the exact details of your business and the sophistication of the parties you deal with in your business, it may be that the LLC won't give you a whole lot of liability protection here.
That said, I do recommend to most of my clients that they form a LLC rather than operate as a sole proprietorship. There is little downside to it and it may end up providing some valuable protection in some situations that you might not be able to foresee now. Forming and maintaining a LLC in Colorado is fast, easy, and cheap. If you want a recommendation based on your specific business plan, see a Colorado business attorney. Besides, to really do it right you'd want the assistance of a lawyer to draft your LLC documents for you anyway, which while it would to the cost, it still will still be fairly reasonable and having a good set of company documents can save you a lot of money and grief later on. You'd also want to discuss with your lawyer how to properly run the LLC to avoid any plaintiffs later succeeding in holding you liable for debts of the LLC through a doctrine known as "piercing the corporate veil".
The bottom line is that it may be that a LLC won't provide you all that much liability protection, but there are also really no downsides to using a LLC for your business. You can, by the way, start out as a sole proprietor and convert to a LLC later if you want, though doing that only helps you for debts incurred after conversion.