Feeling like an imposter

At work this week I offered my third session of a basic business writing workshop. I love talking about grammar, punctuation and writing, and I was ecstatic that people showed up and seemed to enjoy the workshop. (I've even had a couple of people talk to me about writing questions since then, which is awesome!) And while I'm thankful I had the opportunity to talk about writing and help my coworkers strengthen their business writing, it felt strange to stand in front of these people--many of whom are above me in the company's organizational chart--speaking about writing with authority.

I feel a little like an impostor when I do things like this. Even after all I've learned about writing and all my experience in the field/industry, there is part of me that still says "Who am I to talk about this with any kind of authority?"

I know quite a bit about writing. In addition to my degree in English, I've tutored English (college-level), I've taught high school English, and I've been working full time as a writer since June 2008. Theoretically, I should be able to talk about writing and grammar and punctuation and help others strengthen their own writing.

So why do I still feel like I should be in Rutledge basement listening to lectures about Keats?