Just to tag onto this, taking a year off to improve your mental health will only help if you REALLY throw yourself into improving your mental health. Get into speech therapy and don't miss a session, throw yourself into the gym and eat right consistently, throw yourself into low pressure social situations as much as you can to desensitise yourself to your stutter. If you do these things this is a great idea that will probably help when you do go to college. Just please, please don't use it as an excuse to isolate yourself and hide away from the issue. This is a very slippery slope and will only make things worse. Taking the time out is a great idea if, and only if, you actually take the necessary steps to work on and improve yourself.