How to convince our parents for our marriage at age of 17?

Hello! I'm a seventeen year old girl from Andhra Pradesh, India. I met a boy(20 years old) in an educational website last year and we've been in love from past three months. He is from Orissa and is studying in Delhi, currently. We love each other a lot and we, simply cannot live without each other! But, we've very rigid family back grounds. His parents are equally as strict as mine.We have no intention to leave our parents for the sake of each other's company but truly, we cannot live without each other. We, really, don't understand what to do now... In a complete perplexed situation we are. Each of our families consider, love marriages as something very odd. It's much worse in our case as we are from two different states, two different cultures, two different castes and two different religions. But, there is one strong point in common i.e., our love for each other! What is the best step to take so that his and my parents agree for our wedlock?! (We don't want to hurt anyone!)