Ideas are worthless and execution is everything. There are so many companies big and small in education space that I am sure your idea isn't unique, or at least no more than 10% of it is unique (sorry, just my opinion based on actually owning an online education business). You don't have to form a business in order to start, especially if you are not collecting any revenue yet. Business formation is to protect you from liability and to allow formal equity distribution with partners.
S corp is just a status of a Corporation for small business owners that allow you to pass business profit and loss to your personal income. You should consult an accountant on the difference between an S corp and LLC for your local state, because your state or city might have additional tax liabilities that would give you an extra consideration not applicable elsewhere.
Copyright on content is kind of assumed, but you can choose to trademark a product name if you think it's a good one. Registering a trademark doesn't guarantee rights though and can't be enforced, if the name is already in use by other business. You can file a patent for the software, but it's fairly expensive and again hard to enforce without in-house legal muscle. Consult a lawyer on all these cases or at least read up on what they mean online.