I would find out specifically why my parents didn't approve. Is it a legitimate reason like the person is not motivated, rude & disrespectful, abusive, doing illegal things, etc. These are understandable reasons because they will affect your quality of life, security, goals and aspirations.
Or is it a questionable reason like they don't like your partners skin color or ethnic background. These are less important excuses that shouldn't affect a persons love and devotion to someone.
If you are young they probably want you to live life a little more, and have different encounters and experiences.
My good friend didn't agree to an arranged marriage. Her parents are from India and had strong ethnic values. She decided to marry the man she loved, a black man from a different state. Her parents didn't approve because of his skin color, and didn't look at the fact that he was a doctor that loved and adored their daughter. Although it was difficult at first, the parents realized that he was the perfect choice for her. After 6yrs of marriage (the parents didn't attend the wedding) and 2 children later, the parents are slowly accepting her choice. It wasn't an easy road, but she believed in her choice and went into it with open eyes.
Hope this helps, good luck.