Our High School Relationship(M26, F26) completed 10 years.

Hi, I(26M) have been in a Relationship with my high school sweetheart(26F) for the last 10 years. We fell in love in class 11 and have been in a healthy relationship since then.We supported each other through tough times and find great comfort in each other. We both are in government jobs earning well(I am in Group A- PSU service, She is in Group B, govt service) and everything is going good.

We are both planning to marry each other, but due to caste differences( I am OBC and she is SC), we are afraid, it is going to be hard work.

Her elder brother is getting married in March after which he father will look matches for her. My family has political history and take pride in caste rules and allegiances.

I am thinking of telling my father about my relationship but dont know how to? My mother will be against this marriage for sure. My mother sternly advised against dating a girl from SC.She would have been OK with a girl from any other caste Advice me how to approach my family and what consequences can i expect going against my family wishes? Need experience from people who have married their partner from different caste .

PS- Her family will not be against this marriage and both our families know each other as her and my father worked in the same office.