We too often petition fate to overlook the knowns and unknowns that ultimately lead to a "would have if only" statement. I would have taken more courses in writing, listened to my high school English teacher (or college professor) and diagrammed more sentences, or be a true veteran of writing contests -- if only I had known that all those actions or reactions would help single me out from all the unknown writers.
Admit it, you have wondered or are wondering if you have missed your chance as a writer. Sadly, too many writers I know believe that they only get one chance. But that is because we only hear and read about authors who have succeeded (sometimes after dozens of rejections) in getting an agent or publisher to consider them relevant.
I practice being happy for other writers who are making an excellent living through publishing books, whether paper or digital. Book sales show, over and over again, that people are reading and that they read for the pleasure of it, just like many of us write because it brings us joy.
If you have ever transcended the "would haves" through writing, then hold onto that feeling. That covers all the feelings that writing can unearth. And stop listening to your doubts, unless you can turn them into story and that story drives you forward. In other words, we don't have would haves, could haves or should haves with any power to stop us, if we use them instead to imbue our inner storyteller who has no sense of time or space.
Take a peek sometime at the being you once were, and still are, deep down who knows that the story is organic and can't be silenced completely, just shamed to a whisper.