Important: this is not an issue that is going to go away on it's own - you, as the torn party, will need to open a dialogue at some point in time. The sooner the better.
Being from a different culture, even a very rigid or strictly indoctrinated one, does not mean that your parents are closed minded. Give your parents the benefit of the doubt and assume that they will at least listen to what you have to say, even if they won't accept it. But also be very aware of what the cultural reaction to your words may be and know exactly what risks you are taking by speaking up.
Culture and religion are not the same thing, even if they are closely linked. Within any given religion there are "cultures". We often call religious cultures "denominations". Many cultural practices claim to be based in religion but are really based on a man-made interpretation of something related to the religion. There is a difference between religious mandate and religious tradition, even if they are often confused as being the same. Understand that rejecting a practice or tradition is NOT the same thing as rejecting a faith or denouncing your heritage. Don't let anybody tell you differently!
Cultural norms are often expressed in and reinforced by a country's laws. In the Western world there are many laws that often contradict the practices of non-Western cultures. The Western world has laws to support the rights of women and the rights of an individual to self determination, there are laws against domestic violence and controls over what parents can and can not "require" of their children. Bottom line, if a cultural practice is against the law you have other avenues support available.*
Even the most horrendous practice is usually routed in a parent's love and concern for their child's survival within the culture. Different cultural pressures determine what practices a parent considers "essential" and which fates they fear most for their child. It was not too long ago that Western culture held on to some of the beliefs it now frowns upon in other cultures, for example, corporal punishment of children or unequal gender roles and rights. Western culture sees itself as more enlightened and this is often mistaken for better - but what is "better" is always in the eye of the beholder. What you may see as a blatant infringement on your right to autonomy your parents may view as a necessity for your survival within the culture they know. Although your perspective is the one that should matter most where you are concerned, don't feel that your parent's insistance on your compliance with their cultural norms means that they don't love you or care about your happiness. Chances are good that they love you very much and want nothing more than to see you happy.