About 2 years. Mind you, I had a baby in between all of that and had some down time. I'm sure I'd be miles above that if I was practicing the entire time.
Once the idea of echoing simple shapes sinks in, it gets easier. Of course half the battle is overcoming machine difficulties. Much of what was in picture number 3 was the machine misbehaving. Those toe catchers are a result of me moving my hands too fast and the needle too slow.
Hang in there. You'll get it!