“You are as young as your faith, as old as your doubt; as young as your self-confidence, as old as your fear.” — Samuel Ullman
(I guess I’m just a scared old man then. I can be arrogant and narcissistic at times, but I’ve never had either “faith” – by choice, or self-confidence – not by choice. I could probably keep a shrink gainfully employed for quite a while. But, I still consider myself very youthful. Hey, Happy Prime Number Day! Be well and do good, friends.) — YUR
Unclerave's Wordy Weblog 
My newspaper split self-confidence into two lines with the hyphen. I wasn’t sure if it was one single word or two words with a hyphen. But all became quickly clear. Be well and be kind.