I am a Muslim girl from Haryana (India) and my boyfriend is from Himachal as in there area people are little narrow minded. I am now 22 yrs and my boyfriend is 24 yrs and want to marry within 3 yrs. He has already told his family about me but the problem is that how I can convince my parents as they are little broad minded but how I can start this topic?? And my Mom is little friendly but my father also don't say no to my decision but I am afraid how can start.

You could start with introducing him and see what happen.

I am OK with these lines but 1 person how can change the feelings that are already made for him.
But 1 thing my elder brother knows him very well and sometimes normally I talk to my mom about his family situation and my mom every time tells me that take care of him. But then also I am afraid that whom should I talk to this topic in my family first?? :(

You introduce him and ask them, should have done this long ago, if he was possible husband

If your fear is greater than your love, then you are not ready to make adult decisions, or take adult actions, so it is you who must find your courage to walk on the path you want. If your goal is to be married in 3 years, to this fellow, then that the focus, NOT the obstacle you must overcome.

Life throws tons of obstacles at couples, if you two are built for greatness, you conquer them together. If you two aren't meant for greatness together, you conquer them apart.

Thanks for the good reply. This is right that I should not feel afraid. Now my question is this that in my family whom should I talk first for this topic, in my family my mother, my father, my elder brother, my younger brother and me. So help me out whom should I talk to.

Of course you speak to mom first, to test the waters, but do they even know you have been dating for years already? If not they will need time to get use to that idea.