Should my 13 year old son ski/snowboard?

If he ripsticks then I would say that snowboarding would be more familiar to him in getting a hang of it more quickly than skiing. With skiing of course you use both legs seperately and with snowboarding both legs are on one board as it is with a skateboard. It will take a bit of adjustment in feel due to being on the snow and not on cement....but at that age, I am sure he will be doing great in no time.