I want to marry a non Muslim guy who is willing to convert however my parents do not agree what should I do?

Have your parents met him?? If they do not agree, or give blessings to this union, or listen to a trusted leader of your community on your behalf, then you must chose between doing what you want, and the consequences of those actions, or doing what they want.

Not an easy choice, but one that must be made by you.

Parents always want what is best, and in their eyes no one will be good enough for you. It is your choice since you are an adult. Just weigh out your options.

I guess one question is where do you live, and what culture,
If you went against your parents wishes would you be in danger or what would happen. ** please other posters remember there are cultures where it would be permitted to kill a child if they disobeyed the parent and did not marry who they say. So please remember we are an international site and answers have to reflect where they live.