Let her try both.... and nature will take its course....
Kiting is pretty popular with the ladies, I guess because there is a lot of fashion that goes with it, you can get all p1mped up in boardies over wetties and stuff... which can be fun for that kind of folk...... and it won't be too bad for you trying to race her around if she takes it up.....
But let her know, kiting restricts her locations for launching, usually need someone to give you hand intially for launching and recovery... and well, you don't have the time for that when you are out on your board........ so the pros and cons might help her do the maths and she'll see - windsurfing is best