I've worked as an instructor and had people out from late teens to late 70's,if you're ready to have fun then stop worrying and get out there.
Some tracks have novice only days,very easy going and everybody more or less on the same level.
Book a day,and when you get in there and sign in,book an instructor for a session,normally 20 mins,cost around £20-30,they will show you the ideal lines,braking points etc etc and give you a few hints.
But beware,it's highly addictive.