The best advice I ever received about becoming a writer was: "Write! Write every day. Don't miss a single day for three weeks. That way it will become a habit." I was thirty-three. I'm now eighty-one and have written millions of words. These words became novels, works of non-fiction, short stories, essays, letters, poems, and even three film scripts...and I continue to write.
I'd be exaggerating to say I'm a successful writer in that great fame and money have not come my way. However, great satisfaction has. And, yes, I even won the odd award for Creative Writing. But back to your question.
I reiterate: Write! write! write! When it becomes a love you'll know you have succeeded whether you become 'successful' or not.