You won't lose much by not playing the first one. It's more tedious than the second installment, so I would try them in reverse order just for this reason.

The intro of SS2 does a pretty good recap of the first game and from there on SS2 is it's own game.

You don't need to play the first. There are some references to it in SS2 but it's not a big deal.

I’ve heard the first one is a totally different game and that System Shock 2 stands alone.