First, ask them what their fears are about you dating. Try to address their concerns and show them that you are mature and responsible enough to handle situations that may arise. Maybe they have some fears about situations you haven't even thought of, so talking with them about it can maybe help you both look at the situation more clearly, and help you determine your own boundaries before being faced with having to make quick decisions.
How do you show your parents that you are mature? Well, for one, do not sneak around behind their back. If they tell you not to go out with a boy alone for instance, and then they catch you doing it, that is only going to intensify their fears and worries that they can not trust you, and make it even harder for you to get them to ease up on this dating thing. Talk with them about how important it is to you, tell them some of the things you like about the person, and ask them to at least meet the person. Start with asking if you can invite him or her over for a family dinner, or to watch a movie at your house while your parents are home. Okay, I know this might not be exactly what you are thinking about as a cool date, but it could be a good start. Maybe your parent's will see what a nice person he is or at least see how much you like him, or how much fun you have with him.
A second step would be to ask if you can go out on "group dates", where there are a couple of your friends with you, and it isn't just you and your date alone. Like a group of you go to the movies together, or hang out at the mall, or at one of your friend's houses, or whatever it is that you all like to do.
If your parent's still aren't going for it, don't give up, but don't nag about it either. Bring it up occasionally about how important it is to you, and how you feel you are ready for it. But definitely try to drop the subject before it escalates into a fight.
Be creative. Do you play a sport, or some other extra curricular, like being in a play or something? If so, have your parents come to your game, play, whatever it might be, and have the person you like go too. If they are brave, (and I know not everyone will be comfortable doing this, it's just a shot) have the person that you like go up and introduce themselves to your parents, and watch your game/play/recital, whatever, with them, speaking to them, making conversation. Then at least your parents will associate a person with this issue and it might not seem so bad or scary to your parents anymore. Maybe meeting him will help them to ease up a little bit. Again, none of this is a guarantee, but I have known this tips to work before.
Finally, if your parent's just will not budge on the issue of letting you date now, or sooner, and want you to drop the subject because it's only causing fights; it's disappointing but don't let it be the end of the world. It may make you feel very upset now, but they are almost definitely doing the best that they can for you, trying to protect and raise you in the best way they know how. Find other ways to fill your time. You don't need to date to be happy by any means! Fill your time with things for you; things that you want to accomplish, things that make you feel better, things that you enjoy. Learn to play an instrument. Read more books. Write more poetry. Play more basketball. Join a school club. None that interest you? Start a school club. Volunteer. Tutor younger kids or kids in your grade in a subject you are good at. Spend more time on a subject you aren't so good at. Spend more time with your friends. Spend more time with your family. Watch more movies. You get the idea:)
I hope my suggestions help, and good luck to you:)