[akon881]

I am 17 years old and in my partners family girls are married quickly but she wants to marry only to me how will I plan my future and my studies in medical will take more time and my partners parents are of other caste what will do for my future?

[joypulv]

There is no easy answer. I personally would expect her to wait. If she won't, then you must be prepared to lose her. Only you know how much you are willing to sacrifice for love.
Perhaps a formal engagement, a ring, even a contract with her parents for financial settlement if you break the promise.
What do each set of parents say about this? I presume that your parents are paying for your future education for many years to come. Medical schools have arrangements for married student housing, but you haven't even started undergraduate yet. I think you are too young for even an engagement. She and her family should be able to wait until she is 21 in this modern world of advanced schooling.