Science Fiction, Fantasy and Horror writer Neil Gaiman wrote on his blog in May this year, that he felt he wasn't qualified to be at a gathering of scientists, writers, discoverers, artists etc.

Another person at the gathering told Neil Gaiman this:

“I just look at all these people, and I think, what the heck am I doing here? They’ve made amazing things. I just went where I was sent.”

That man was Neil Armstrong telling Neil Gaiman he felt he didn't belong.

So in other words, if an accomplished writer and the first man to walk the moon can feel imposter syndrome, then everyone can.

That doesn't mean, you're an imposter!