Hi Fairlie. It's not really about the number of years or projects, it's about the depth and breadth of experience. Like many other developers, I started my career writing code and taking instruction from more senior people on the team. After a few years, I gained experience and gradually started taking on larger and larger design tasks, until I was the person responsible for the technical delivery of a software system. For me, the architecture role is a role that you evolve into. Since the software architecture role is a technical leadership role, the "soft skills" (confidence, influence, communication, motivation, etc) are also important too. This article that I wrote for InfoQ might help you answer your question ->
http://www.infoq.com/articles/brown-are-you-a-software-architect