Let's unpick that a bit. Suppose I'm reading slush for an anthology (I am, right now, and it's science fiction meaning very few writer stories but many, many coming of age ones) and my job is to separate the stories into two piles: 'possible' and 'impossible'. The first thing I ask my editor is how many writer stories and how many coming of age stories he'll accept. 'One writer story,' he says, 'and we'll take as many coming of age stories as we think are good, but only if there is some real value to the coming of age bit.'
That means that in the possible pile I'm going to put maybe two writer stories. All the others, no matter how good they are, will be rejected. If that was your perfect piece of polished prose, tough titties, my friend.
The coming of age stories? Well, I'll probably put a dozen in the possible pile. That means I'm still rejecting hundreds of good stories - because I've filled my quota.
Now let's imagine I'm reading slush for an online literary 'zine that publishes four times a year - they would probably accept one writer story every other issue, and one coming of age story every issue. That means that for most of the year I will be rejecting one in seven stories with a writer as protagonist, and one in five stories that are coming of age based, simply because they don't fit with the balance of the 'zine.
Writers love writing about writers - readers are not that enthralled to read about them.
Coming of age is something we all do - but literature is capable of so much more than simply pinpointing the moment a protagonist stops being a child.
Now, of course, you're telling me this doesn't apply if your story is that perfect piece of polished prose, but look at the odds you're giving yourself. Not only does your story have to be unutterably wonderful, but it has to get to the editor's desk before any other unutterably wonderful 'writer' or 'coming of age' story, or the editor will already have accepted his or her quota and you'll get one of those rejections that says, 'we really liked this but it's not right for us at this time'.
So if you want to be a published writer; write about chocolatiers or welders; think about death and betrayal and hope and fear as subjects that extend throughout life, not just as emblems of that pivotal moment when your protagonist loses the delicate bloom of childhood.
It won't guarantee success, but it gives you a much better chance of being in the 'possible' pile, and if you really have written perfect, polished prose - then you're on your way to being a writer.