I was pretty much grown-up by the time I attended school in Britain - or as grown-up as I'll ever get.
Now I have to motivate myself much more than I had previously.
Try to meet as many authors, agents, and editors as you can.
I went to college, though I didn't take many writing courses.
I now have to find a reason to write, every single day.
I found college useful for a lot of other reasons. It exposed me to a great many influences I wouldn't otherwise have encountered, and gave me a lot of time with some very intelligent people whose thoughts are still with me.