Oh, the number of people that have asked me this one! It's a gray area, folks. A really, really gray area.
In a sense, yes, I am Marian Moyer and she is me. The soundest writing advice is to "write what you know" and if I know anything, I know me. So when I come to a fork in the road for Marian Moyer and I don't know which way she'd turn, I ask myself what I would do in that situation.
8 times out of 10, that's what Marian does, too.
She also looks a bit like me, I suppose. The hair. The freckles.
I can see where readers would get the idea that I turned myself into a storybook character.
Of course, there are a lot of things about Marian that are NOT me. At. All. And while I can't help but incorporate bits of myself, my friends, and even my family into certain characters, no character is EXACTLY like someone I know–including myself!
Clear as mud?