First of all, your parents are playing a very dangerous game, because if they keep this up, they will push you farther and farther away.
They have put alot of time and attention into raising you, and if they did a great job (and it sounds like they did) they need to start trusting your opinions, not agreeing with them, BUT recognizing them.
If you can, discuss this with someone YOUR PARENTS respect, and then have a meeting with the 4 of you, it is possible they will hear what you have to say and give you the room you need to grow.
I discovered, a long time ago, that a written letter works far better than a conversation. With a conversation, the people you are talking to are formulating their answer and NOT listening. With a letter, they will read it, get angry, hopefully, re-read it and give it some thought. THEN it is the time for conversation which will be far more productive.
You are growing up and your parents are afraid, they are afraid you are growing away from them. Which you are and which you should.
The boy you marry MUST be of your choosing not theirs. You know what you want, they know what they want for you, BUT, if you are ready to get married (when you are) you are ready to chose the derech you wish to live.
If intervention with a third party does not work, you will have to either go along with their choices, or make some hard choices of your own.