If your local club has a bowling pin shoot, that is a good way to start. Especially with a .22lr...cheap to shoot, and a bit less "work" than a big bore. IDPA is excellent as well, cause you don't need a fancy (ie Expensive) race gun to compete. Plus, it has the bonus of being a little more like 'defensive training' than IPSC.
I have found a new passion...sporting clays. I hated it the first few times I tried it...always missing, and my shoulder hurt a lot! But man...after my first 5 in a row string....I am digging it! Not even competing yet...just me and a friend out busting clays.
As far as knowing whether or not you're ready, or how to tell if you're improving...well. That's pretty much up to you! I figure if you're doing well to yourself, and having fun while doing it....who cares if you post the top score or the fastest times!!
"Dreams only have meaning because we struggle in the waking world."
-- Major Motoko Kusanagi GitS:SAC
Member of NRA and Western Missouri Shooters Alliance