At what point do I say to myself, "Self, you're pretty much a no-talent writer and you should give this all up. Your view of the world is not what everyone else's is. Your writing style sucks grapefruit without sugar; and you're too dang short"?
When you're standing at the Pearly Gates and St. Peter is busy discussing his novel with Miss Snark.
Look, writing is supposed to be hard. It's supposed to be utter agony. If it were easy, there would be no trees left at all, and what would Killer Yapp whizz on in Central Park?
If you must write, if you love to write, if writing makes you understand yourself or the world better; if writing is prayer; if writing is fun; if writing is what you think about when you see something strange or wonderful in this old world, then write.
If it's never published, so be it. YOU will have loved, understood, empathized, prayed, rejoiced and enjoyed. In the end, that's all that matters.