I assume this was not an arranged marriage judging by other posts I've read it sounds like what is known as a liberal marriage.
My cousin is married to a chinese girl and the dowry is usually set out in the marriage agreement, which I suspect you did not even have.
The dowry doesn't necessarily have to be money it can be clothes, jewellery, land ot whtever is agreed. It is supposed to represent compensation for the family losing their daughter. It should reflect the wealth of the groom's family and in return the family should provide a meal.
Doesn't appear that other traditions have been followed so seems strange that this should be with a set amount. I think your wife has decided the amount.