How does one tell?

Yesterday, around New Xiang Ji at Farrer Road, I saw one of the fabled Nanyang Girls with Long Hair. Apparently they are restricted to black hair accessories, just like those at Raffles Guys School are, but I guess long hair is already a great concession. Was this person Primary 6? Or Lower Secondary? There was a green nametag, the only clue I've got. Didn't manage to see the socks to see whether they said "NYGH" (are those compulsory for all from the School With The Most Indecent Uniform In Singapore Bar One?)