Should I play through X/Y before S/M?
I dont own a 3DS yet
I'd say yes. X/Y was lots of fun for me.
Do you want to play pokemon now? If yes, buy XY. If no, wait and see how you feel. I liked the game.
Nah
If you need something gen6 to play, pick ORAS
It's not as good as it should've been, but it's got more content than XY did