Have you considered taking classes?  It's never too late to start...

> I would like to know how different an experience is it to perform to music > that is recorded compared to a live orchestra. Does a live accompaniment > actually help your performance on stage?

Live music is less consistent.

> When I first saw Swan Lake on television I was amazed at how slow the tempo > was compared to the cd's I have.  Is the normal tempo of a recording too > quick for a dancer to perform to?

The tempos are often changed for concert recordings because of how the musicians feel it should sound, irrespective of dancing to it.  You see this even in non-dance music --- tempos vary widely depending on the musician.

You can dance to any speed of music, given the appropriate choreography.  And don't get me wrong, dancers can dance very fast if we want to.  But if you already have the choreography, there is a certain speed that works best.