This is a great place to learn new skills. I suspect you'll find your tech writing is a great foundation to expand from. (Dang, ooooold English major here; I still want to write: "from which to expand," and NOBODY talks like that anymore.)
If you have any questions, about writing or this site, please feel free to ask.
Take your time, no one will put a stop watch on you.
As for the tech writing, Don't let that worry you. I have a number of decades in tech writing and am still in that industy, didn't discover fiction writing till a few years back. Yes, there were things to unlearn, but not that many. I found my tech writing skills very helpful in writing fiction, not just in the grammar/technical areas but also with respect to description and conveying information.
And I've also found my tech writing has improved as I increase my fiction writing skllls.