I'm a professional writer and much much older than you.
Writing, sometimes, is hard. The more you aspire to excellence, the harder it can become if you let it. And you should aspire. You're never good enough.
Here are a few things that may help from my experience.
1) Relax and enjoy it.
2) Separate the creative process from the editing process. That is, on first-draft just let it flow. Write anything and everything that comes to mind. Don't worry about vocabulary, spelling, grammar, political correctness, offending your dog. Just get it out. Put on your editor's hat only after you've sputtered out. Then go back, rewrite, and edit. Fine writing is REWRITING. Sometimes many passes; many drafts.
3) Keep a notebook. When your mind tickles you with a phrase about anything, write it down. Your subconscious mind is your best friend. But it's shy, easily offended. Censor yourself and it'll shut down. Invite it in and it'll serve you with ideas, images, and language of startling beauty and relevance. It'll also deceive you into believing that something it delivers is better than it is. But you can deal with this during the editing/rewriting phase.
4) Give yourself permission to write. And to publish. Keep in mind that you can't please everyone with your writing. No matter how fine a writer you are, some readers will reject you for uncounted reasons. Your goal as a writer is to minimize the number of readers who do so.
5) Writing is simply another way of talking. You talk naturally. If you relax, you'll learn to write naturally. To write well you do need to learn and absorb the basics of spelling, grammar, logic, formatting conventions, etc., etc. These technicalities should be internalized like muscle memory. But don't worry about that crap while writing the first draft. Just get it out.
The Erlang community has done a great job so far as it goes, but still needs help.