The first part sounds like a play on the Picasso quote "All children are artists. The problem is how to remain an artist once he grows up"[1] and the second half sounds like something Ken Robinson said in his TED talk about creativity[2].

What's interesting about the underlying implications of all these quotes to me is that what makes a good physicist, a good artist, or a good anything, is the unabashed curiosity, a willingness to experiment without being stopped by fear of failure, and the state of play that one must be in to unleash creative approaches and new connections.

[1]http://www.brainyquote.com/quotes/quotes/p/pablopicas169744.... [2]https://www.ted.com/talks/ken_robinson_says_schools_kill_cre...

The version of this I have heard is "The creative adult is the child who survives"