You never really answered the question: why do you write?
Why do I write? Because I love stories. They illuminate the world and spark the mind. They speak to the heart like nothing else. They have tremendous potential to fill the world with goodness. I think of my own childhood favorite books and the way they've had huge impact on my pursuit of meaning and happiness.
Given all of that: of course I want to create stories. How could I not want to share this good and beauty with others?
How long have you been writing?
In the sixth grade, a friend and I wrote a series of short stories about Chip the Cookie and his rivalry with the muffins across town. I started a book in eighth grade which earned the notable distinction that my mother liked the first page. It was the tail end of Sophomore year that I wrote a full length fantasy novel, and have been writing consistently ever since.
What do you suggest to beginning writers who want to learn?
Write. Don't worry about making anything good -- the mere fact of sitting down and creating a story is worth celebrating. With time, they will improve. There will be dull and boring moments, yes, but be consistent and the fruit will come.
But how do you become a good writer?
Unfortunately, there are no shortcuts. Create a habit of writing, and the skill will come. It took me a long time (years!) to get a basic competency with storytelling, and there's still much room to grow! It is a lifelong habit to foster.
However, there's an idea of 'the gap," linked here, that has reassured me countless times. I hope you find value in it.