I had similar feelings with the first creative writing class I went to. One student shone, her work far better than any one else's. I struggled with the exercises, especially free writing - there's something about being told to write now this minute that freezes my brain - but this student was brilliant. The words flowed, her imagination apparently boundless, flair and intelligence combined into delightful prose.
And yet, and yet. And yet I am published, and they aren't. I remember my fellow MA student, how she announced that she'd finish her novel if an agent or publisher was interested, but wouldn't waste her time otherwise. I remember the student I was so overawed by, and know that she - despite interested enquiries from agents and publishers - refused point blank to even consider changing a single word of her novel.
I remember them, and realise that sheer natural talent on its own isn't enough to make a writer. A whole raft of abilities are needed and close to the top of the list are the ability to finish work, and the ability to work with others. Which I find pretty comforting, to be honest, because those are things we can learn to do.