Teach the ACTION (the yarn gets wrapped, the wrap gets pulled through, the old stitch gets slipped off...)
and ignore (for the moment) which hand holds the yarn.
after a few rows--talk about holding the yarn.
show her you method.. and others..
there are lots!
European (ie continental (left hand yarn hold)
English (right hand yarn hold)
Combo (usually left hand yarn hold)
Portuguese (Usually left hand yarn hold, and done 'reveresed" --that is PURL is main stitch, and knit stitch is similar to norwegian purl)
(portuguese is a form of eastern uncrossed!)
--and yes, knitting, like typing or driving a car is a 2 hand activity.. doesn't matter if you are a lefty.. you drive the same way! (and in the days of hand cranked car windows, rigthy's learned to roll down the drivers side window with their left hand (to pay a toll, or to just open a window!)--(and lefty's learned to change gears!)