Since When?

Since when did the name Diana became a Nama(name) Malayu??

While I paying for my groceries at EconSave today, the cashier took a look at my credit card and had a surprised look on her face.

Cashier : (looks up at me)"Diana... ?! You masuk islam ya ? Nama Malayu.."
Me : (smile)"Diana... actually ialah nama English.(actually is an English name)"
Cashier :(disbelieve look)"Tak lah, Diana adalah nama Malayu." (No, Diana is a Malay name)

erm... here is an 18 year old little Malay girl telling me that the name Diana is a Malay name. Since when did that happen?!? Why wasn't I told about it?!?! Sigh.. head scratching, mind boggling stuff this is! :p