The Difference Age Makes While Singing

I am an observer.  Some people call it creepily staring... I prefer observer.

A few weeks ago I was at church and my eyes began to wander and observe as the congregation sang.  I noticed two things:

1. My arms are way hairier than the lady's arms across the aisle
2. The older generation sings completely different than the younger generation.

Because some things are much better acted out than written, here's what I watched unfold:

(If you're having trouble playing this video, just follow this link!)

So when does this phenomenon start, exactly?  Is there a specific age?  I hope 50 is the magic age.  I want to turn 50 and BOOM! I sing with so much vibrato that the Earth quivers.

-Amber