When I was hired for my first position in Project Management, I didn't know what Project Management was. Thankfully, neither did my employer.
I didn't mislead them in any way. They just didn't realize that the skill set they were looking for was contained in Project Management. I had the skills they needed to get started, to which I have added education, experience and a healthy dose of panache.
I'm a CAPM and CSM, soon to be upgraded to PMP and CSP, respectively. This is my third career, and I love pulling all the disparate pieces and people of a project together, and bringing clarity, common purpose and drive to projects.