Convincing the orthodx parents for a marriage in the same caste with different subcaste

Hi every one My name is Ramnarayan I am facing a problem in convincing my parents for my marriage. the problem goes like this i work in a agri institute i earn Rs 20000/month. my parents started looking a bride for me from last one year i colud not find any match. finally i could find a match in the institute but she belong to same caste but different subcaste.Ii told my parents about the girl and explained every tradition they follow.My parents are orthodox and they strated rejecting the proposal by giving the reason that they dont have this tradition that tradition.I tried to convince my parents from the family members like my uncle and sisters husband but they are still sticking to the old traditions. my parents are sentimental they speak about how they cared us althose things. I want to get married with the blessing of my parents and my match needs the same.Their parents were agreed for the marriage.please give me advice and suggestions in this regard