I'd written some poems, jokes, short stories, etc. but didn't get pubbed 'til I was 40 and my back went out. I had to retire and that's when I decided to fulfill my dream of seeing my work in print.
I've never written a poem in my life. I recently came across some of my mother's high school material and discovered she was her class poet.
I worked as a junior (very) copywriter for a small NYC ad agency when I first got out of the Marines. I bounced from there to college, where I got a BA in English lit. That requires a lot of writing, or did then, so I progressed to an editorial job at the local educational TV station--WMHT in Schenectady, NY. That was a monthly requiring program descriptions and short articles. That jobg also required layout work for the magazine, something that made me happy that letterpress had faded.
When I graduated, I couldn't find a job, so I freelanced. Actually, I started freelancing in '68, and went on to full-time freelancing in '70.
It ain't what it was, though. Fewer magazines in my fields. Lower pay in almost all fields. Various content mills looking to put the blocks to any writer who is hard up enough to work for them. More scam artists per square inch. The Internet has been a great boon, but it is almsot as great a curse, both for writers and for people who just want to get information.
Add to that a generation, or two or three, that believes information wants to be free--it's inanimate, for Pete's sake--and problems increase.
Whoops. Enough of my diatribe.
Yes, I did write before freelancing. Almost all the successful freelancers I know were professional writers at one end of the scale or another before going on to freelance work.