I definitely disagree with her! I frown upon girls who have rules about what ring the guy must propose to them with.
The ring should not be a price the guy has to pay to marry her! If a one's gf demand a specific ring price, one should really think about whether she's after his money or she's really truly in love with him.
I remember those days... you're also not allowed to go into the arcade if you're wearing school uniform!! To this date, I still haven't been to one. =( I would make it a point to go to one next time I'm in HK, but I'd feel too out of place.