If this is your goal then start her on skis, no question.
If you watch most of those videos with kids under 4, none of them actually turn onto their toeside edge, basically they sideslip the whole mountain. Im not knocking it - as long as the kids having fun, but thats not snowboarding, its sliding the mountain on your heels. Until they turn, they are never more than a level 1, steeper terrain - don't even think about it.
Put your kid on skis, there is actually a chance you get to ski with your kids for some of the holiday.
Managing parents expectations is normally the most difficult part of working at a ski school.