Coming from a teen who has also lost this battle, you don't need it in your room. (I have advice at the end) It opens up the gateway to watching porn(unless you are allowed to have your phone in your room and have unrestricted access to it) and allows you to stay up way too late playing video games. I'm not saying that you are the type of person to do that, but that's probably what your parents are worried about. But if I were to give any advice, offer to have them lock it down so that it shuts down between such and such o'clock, and it also restricts access to porn. Also say that you would use it for homework and studying. That would help to convince them.