This is actually a good question. There's no reason that you have to permanently give up formal education to go start a company (or anything else for that matter).
I made exactly this choice (slated to take 2 years off, but same idea), and definitely see myself returning to school in the future. Perhaps when I go back I'll be a wiser person. An even better student. My school says it'll be happy to have me back.
In the meantime, I can pursue my crazy ideas and try things, taking risks I might not like to as I age. Building something whose time has come.
The relevant chorus to the Byrds' song "Turn Turn Turn" goes:
