If you want to write, then do it. I wasted a lot of time just thinking about if I should write and then when I finally did it, when I finally wrote my first book, I wanted to kick myself. I found something I truly LOVED to do.
But you know what? I stunk! And I knew it (because I read a lot, I know what's good and what isn't, and that first book wasn't good). So I joined some writers groups. I followed writer's blogs. I took class after class after class to learn the craft. And I wrote the next book. And the next.
Having a writer friend you can share each other's work with is also a great way to learn. When you spot your own errors in someone else's work, you may tend to make the mistake less often in your own.
So, if you want to write, then write. The only thing stopping you is YOU.