A couple of thoughts:
1. You will be personally liable for any infringement that occurs during the period when you, rather than the LLC, are selling infringing products.
2. Why not form the LLC right away? It can be done quickly and inexpensively. You might find the post at the link below helpful.
Disclaimer: This post does not constitute legal advice and does not establish an attorney-client relationship.
Both lawyers above are correct. This is just to make it clear that "first to use is first in right" under US trademark law. You don't need to register to have a trademark. So, I would recommend that you rule out as best you can any potential pre-existing, similar, and significant trademarks used in your industry prior to using your trademark.
Proviso: The above information does not constitute legal advice and does not establish an attorney-client relationship between us.
I don’t see much connection between your infringement and registration. If you’re infringing, then you’re infringing, whether you have sought to register or not. I suppose that filing might alert the other party to your use of the mark, but that is not generally a big problem. The first thing that will happen is you will get a letter from an attorney asking you to cease and desist. At that point the infringer generally promises to stop infringing, and that’s the end of it.
If you are investing major funds in advertising and marketing with the mark, you cannot be so cavalier. In that case, however, you should have obtained a “full search” from one of the trademark search houses plus an opinion of trademark counsel and have filed for the registration before you start investing in the mark. So I recommend that you set up the LLC now, get the full search immediately, and then file for the mark. Actual use will give you a common law trademark with priority over later filed marks in the area in which you have actually used the mark.
DISCLAIMER—This answer is for informational purposes only under the AVVO system, its terms and conditions. It discusses general legal principles, trends, and considerations and is not intended as specific legal advice regarding your question. Each state has different laws and the answer could be different if all the facts were known. Full evaluation of your legal situation would require personal consultation permitting an understanding of all the facts and circumstances. This answer does not establish an attorney client relationship.
(Bryant) Keith Martin