I'm sorry, but your Winston Churchill quote, although commonly attributed to him, is a misquotation. François Guizot, a French historian and statesman (of whom you most likely have not heard), originally said, in the mid-nineteenth century:
"N'être pas républicain à vingt ans est preuve d'un manque de cœur; l'être après trente ans est preuve d'un manque de tête," which translates roughly to:
"Not to be a republican at 20 is proof of want of heart; to be one at 30 is proof of want of head," republicans being the liberals of the time.
And he did not ever take the quote and modify it, or use it in a witty way such that the quote is attributed to him.