Yes, I agree on getting out of your comfort zone id good and writing your own code / working on a small project is an amazing way to learn!
But it can also be discouraging when you get a problem and you don't understand anything xD
Thats why I think it would be better with a small amount of knownledge, so you at least have an idea of what is going on.
I will 100% use Code Wars in the future!
If you get to a problem and you don't understand anything you likely haven't broken it down small enough.
There are times (and a lot of them) where I feel I am absolutely clueless how to solve a problem.