If you have llittle mechanical knowledge, maybe try an 80's Corolla, its a far more forgiving place to learn. Things don't break as often.
As most have said, the Mini was thought-up (maybe only half-baked?) in the late 50's, using technology that was already out of date. You really will have to be switched-on with general mechanical stuff to get yourself out of the trap of spending waaaaay too much money at the local Mini specialist.
Mini's have:- Under-powered motors, weak gearboxes (especially if you think you are Sebastian Loeb) woeful drum brakes, cr@p electrics, and unfortunately, some have had some pretty unforgiving previous owners.
If you do eventually decide to jump in and get one, drive as many as you can before you lay the cash out. Hell, you may not even like 'em. None of my mates 'get' the whole Mini thing.
Get the best/nicest one your pocket can buy you. A second-rate car that lets you down every third time you drive it is a sh!tful experience that will leave a very bitter taste - A very nice car that has been looked after well can give you SO much more enjoyment, and less greasy hands.
Try to find one with disc brakes, even if it only has a stock 998cc running the show.
Embrace some of the technology that is so easily available. Don't stuff around with bloody points ignition, throw in a Pertronix-style, electronic ignition setup. Best $200 you could spend. Oh, and a worn carby will ruin the fun, too.
When it breaks down (and it will) fix it, properly. Don't bodge it. It will only break down further from home next time.
But hey, all we ausminier's have had one, (usually more

) and we all love driving what is so much more than transport. It is an 60's icon that will get under your skin and possibly lead you on to much more enjoyment than most cars. Oh, and people tend to remember your car, not you.
You may have one for a month and sell it. But you may end up with an addiction, too.