Well...that's the advice I have as well...
JUST DO IT!!!
You really can draw, or create a card image as many times as you wish. There's no hard and fast rule that says you can't have a bunch of early versions or prototypes.
You may have more than one deck in you, and that's OK too!
I created a deck by not thinking about it at all...just getting some blank cards and a Sharpie and setting a timer for 5 minutes and just making a card as fast as possible.
It's a good place to start...as you may get symbols that are revealing, but you don't know why until later study.
Or you may end up with something you can later refine, redraw, and rethink.
Or you may just end up with a project that took two days work and becomes published and helps you pay your rent.
You never know.
But the best thing to do is just begin...and see where it takes you!