cajuntexasman,
Interesting question. I know of many examples of 15-year-old young people who enjoy learning and just as many who would rather play with their Ipods or X-boxes! 

The same is true of the balance of the quote... we are all individuals and whether we are 30, 40, 50, 60, 70, or 100 we are likely to believe ourselves in an altruistic light, yet act in various other ways - some negative and some positive. 

I believe the quote is meant more as a manner to strive to meet.  An altruistic, introspective approach to life.