Re: Marriage of my choice
Islamically, your parents have no right to force you to marry a particular person. They have to ask your consent if you want to be with a certain person. What your parents are concerned with, marrying in family, in caste, society, status, mainly forcing you into something, goes against Islam.
Ask them what their reason is for not approving of hte girl, other than status and caste and society.
Also you have to consider this: are you going to live away from your parents after marriage (whoever you marry)? I ask because IF you do marry her and you bring her into a joint family, they might make her life a living hell. Do you really want that for her? On the other hand, if you have some sort of distance between you and your family, the parents are more likely to come around.