Don't beat yourself up and be a negative nellie... you wont get anywhere that way. Think positively and logically.
You will need to get a tax id and sales and use tax id. you will have to file the proper reports quarterly with each entity and pay any taxes due. Even if you go to a free set up and make sales, you still have to file reports or the IRS and state will be after you.
I am not familiar with online sales and sites so I can't answer to the tax forms, etc related to that. You would need to look into it just so you are covered either way.
We own our company and a huge part of my job as owner is making sure I get payroll taxes paid monthly and all reporting done quarterly. There is a lot of paperwork and I am the one in the family who is most organized with that part. Hubby does the selling, negotiating, etc and I do financials. It is a team effort but well worth it for us. We are full time and live off our salaries paid by our company.
You don't sound like an idiot just because you ask for information. Any person in their right mind would gather all information befor making a decision so they can make an informed decision.
Good luck to you!