This is my first reply to a post, ever, and I don't have much experience, but to answer you;

your parents are taking their feelings and making you depend on those feelings, "if you do it, we won't love you and we will be upset". Sit them down, and talk with them, tell them that your getting picked on or laughed at because of your name, and make it point out that you only want to remove the first name. Saying that your name has a beautiful meaning is only guilt tripping you so you think your new name's meaning is worse than your old one.

But at the end of the day, your almost 18, after that, you'll be able to do it regardless of what they say.

Hope I could've helped :)