I have only been writing seriously (fiction) for a little less than a year now and am just now barely scratching the surface of figuring out what kind of writer I am and what type of writing I want to produce. I have also come to the abject realization in the past couple of months that I am not ready to be the kind of writer I want to be. This lucky realization has probably been the best and worst thing that has happened to me so far. Best because I am no longer naive and cocooned in a "everything is possible as long as I just write and try" world, and a worse because the steps I need to take to get where I want to be are risky. Either way, I've taken the initial steps and plan on investing properly in them to get the best out of my return. I have been published in non-fiction, the first of which occurred in high school, and I have also been lucky to have some of my artwork published and sold all before I was 17 - but in every single case it has been an outside source that has either approached me or put me in connection with the right people. I don't consider myself to be published because I have never sought formal publication with intent of seeking publication; I was just lucky the times before. But currently, I write a lot of non fiction, both for academia and work, and am also a volunteer grant writer for my local art museum. It's great, but it's also safe for me as it's not non-fiction.
This happened to me fairly recently. I realised I was trying to force myself into writing in a way that didn't really suit me because it felt necessary to the story. I am still yet to move passed the second chapter and so I've started on something more fitting. Ever since I was about 6 I said I wanted to be an author. By the time I was 13 I had started really getting into writing. I'm now 19 and have spent the last year and a half writing more seriously. I would like to be published by the time I finish uni - in another 3 years but if I'm not I can't imagine I'll give up.
I've been writing since I was about seven - I used to honestly believe that I'd be "the next JK Rowling" until I was at least thirteen. Then I realized that I was kind of crap at writing, but I never stopped. Even if I won't make money from it, it's a fun hobby.
I've been writing since the third grade (I'm 27 now). I wrote silly stories staring my friends and I until around junior high school, when I started writing fan fiction. Sometime in high school I started writing REAL fiction (with made up characters and everything!), and have been doing so ever since, though I still write fan fiction on occasion. So I've been writing for approximately 18 years or so....and haven't published anything yet. lol Honestly, I think writing is something I'll do for the rest of my life, even if I never publish anything. It's just something I've always enjoyed, even if I'm the only one who ever reads it.