Do it in person. If its something that you don't enjoy then there is no shame in that! If you quit in person that'll make you seem mature, but if you quit by phone then it'll make you seem childish.
Do it in person.. I helped one of my old coaches this season and all of these kids were 11-12, four of them quit and they did it in person. So if they can you can, its not that hard we dont get mad just disapointed