I tried snow skiing to no avail.  I'm thinking snowboarding might be easier, though.
Snowboarding was developed based upon inspiration from skateboarding and surfing.  If you think you'd like those sports, you'd probably like snowboarding.
I can't say I've tried those, but since the board is wider, I think I could last longer.
The stance is a lot different on a snowboard.  With ski you are facing forward as you ride. Snowboard stance is to the side.
I think I could handle that.  Have you tried it? If so, what is the hardest part of learning?
Yes, I've tried it. I grew up skateboarding.  The hardest part for me was having my feet actually secured to the board.
Does it have a non-skid surface, or is it slick?
Your feet are mounted within bindings on the board, like on skis. The top of the board is slick like skis.
I guess if they are mounted that would be okay.  How hard is it to get back up after you fall?  LOL I really need to know!
It isn't too difficult.  The board is wide, like 10 inches, but the bindings are easy to release.  It's fun.