Youth is not a time of life, it is a state of mind ; it is not rosy cheeks , red lips and supple knees, it is a matter of the emotions : it is the freshness ; it is the freshness of the deep springs of life . Youth means a temperamental predominance of courage over timidity of the appetite , for adventure over the love of ease. This often exists in a man of 60 more than a boy of 20 . Nobody grows old merely by a number of years . We grow old by deserting our ideals.