How many years does someone work to become a doctor? There's 4 years of college, then 4 years of med school. 8 years total of schooling. But then there's at least 3 years of residency. What if we considered our writing careers the same way a prospective doctor considers theirs? Think about when you first got serious about writing. No, I don't mean when you first got the idea you might like to be a writer. But when did you get down and dirty and make the decision "I am going to be a writer." Three years ago? Six? One?
Someone doesn't one day decide they're going to become a doctor, and the next year they're operating on someone's leg. Why would writing be any different? What I'm saying is this: We need to give ourselves AT LEAST ten years before we can even start to doubt ourselves. :)
I bet every med school student has doubts, too. But the ones who succeed, the ones who become successful doctors, are the ones who keep going. Keep pressing on. Push through the tough days.
You CAN do it, writers. God has put the desire in your heart for a reason.