You'll need a legal entity.  And you'll be dealing with cofounders, compensation, contractors, hiring, accounting, and lots of other challenges.  And life will be much simpler if you do your homework and set up these early start-up operations the right way!  

Because making mistakes in setting up your company and your operations can create major headaches that can cause a lot of stress, cost a lot of money, and even kill your company.  Do your homework!