Let's just make sure we are all on the same page.
You state "or would I put the date that the company was technically incorporated.....".
Is this an accurate statement? If so, you are needing to file a separate business tax return in addition to your personal tax return.
Registering with the state does not necessarily mean you are incorporated.
So please clarify so you can get proper guidance; are you actually incorporated or are you just a sole proprietor?