I once thought he sang 'age 17' too. I listened again today, and I'm pretty sure now, that he is singing 8:17, a time reference. Like in some of the other songs (Breathe, Unknown Caller).
The way I understand it from 'Your face' to 'faith in the/a clown':
Your face (as in the verse 'face was like snow', white as snow) = you were innocent
your grace (as in God's grace) = you loved me unconditionally
can of mace, in your case (a defense weapon in your case) = your defenses
And you put it down.... on the ground = and you surrendered to me
8:17 (a time reference, a moment) = the moment of surrender
Don't lose your faith in the/a clown = don't lose lose your faith in me, even if you now find me ridiculous, imperfect.
In Oakland Bono sang 'don't lose your faith in this clown' like he was talking about himself, and I've read fans saying, they think it comes from 'the holy fool in Christian tradition'.
Try and Google that and see what you think.
Or there's a link here:
Foolishness for Christ - Wikipedia, the free encyclopedia