Yes, giving up meat is something that only you can decide to do. You won’t find as much success if you’re forced to change your diet, or if you’re doing it in order to fit in, or because a celebrity told you to do it. There’s just no personal reason behind it otherwise. Part of your strength will come from thinking through your reasoning for becoming a vegetarian or vegan and then deciding, definitively, that it’s something you want to continue with, be it for health, religious, ethical, or environmental reasons. No reason is bad as long as it has a personal relationship with you and how you view both the world and yourself.