Stephenie Meyers is quoted as saying that she might not be the best writer but she is a good storyteller, and she's ok with that.
I tend to agree with her. I think you can become a writer but you must be born a storyteller. Learning to write is the same as learning any other skill. Classes are held to teach the basics, workshops offered on every aspect, and countless how-to books are available to purchase at your local bookstore. You can even obtain a degree that will look great in your bio.
None of these will make one bit of difference if you can't tell a story. If you cannot breathe life into an idea, and make it live beyond your imagination then all the knowledge of the craft in the world cannot help you. There is a reason that being a writer is considered an art. There is a part of it that cannot be taught. It is a talent that lies within you.
If writing were like tending a garden, then your talent would be the seed. The soil you planted it in would your experiences and your voice, the richer the better. It could grow from this alone but if you want it to be truly glorious you must water it. That would be the knowledge you gained about your art. It doesn't have to be a lot in some cases. In fact if you over water it, you will most likely kill it.
If we follow through with this analogy, then your agent would be the fence that surrounds your beloved garden and protects it. Your editor would be the Miracle Gro and the marketing department would of course, be the fertilizer. I mean that in the nicest way possible. All of these steps are needed to create the perfect garden that is your story.
But remember, it starts with the seed. So if someone tells you that you might not be the best writer but you are a good storyteller, take it as a compliment.
And tend your garden.