I am ready to change my religion. Please help me. Suggest me how can I approach her parents and ask them for their consent?

All you can do is ask and present yourself (financially, emotionally, physically) in the best possible light.

You could talk to a Muslim cleric for advice, preferably her parents'. Showing that you have started might show your intentions.

Do all in your strength if you truly love this girl to show how much you love her and want to marry her but this may cause trouble in your relationship with your family try and talk to your family about it and if they accept give it all you have got