That's a good start to driving, having no faith in your own abilities!
I've never, in 27 years of driving, had a fault accident. I'm no saint but then again we cannot be alert 100% all of the time as there is always some numpty out there intent on spoiling our driving pleasure!
If, for your own benefit, you feel you would be better cutting your teeth in a shed, then go for it. Once you have the confidence then do as you suggest. I do understand, two of my three daughters have had a shed for a first car, one has an MGF now, the other a Scirocco GT classic one. Their first car luckily was a shed as they both mullered them in the first couple of weeks. I spent many a weekend beating the dents out!