It's been my experience that Easterners are prone to fall to peer pressure. I hope some of your Western individualism has rubbed off on her. ( But not too much though, because if she *want's* it cut, there will be no stopping her then! )

I could see cutting a couple of inches maybe, so she doesn't sit on it. But no shorter than that. ( and as long as she doesn't go for one of the more more extreme "traditional" hair styles like the Queen's of past ages had in some pictures I saw at the Oriental Hotel in their historical display. )

pom yao suai ma!