If this is what stops you from practicing, then don't worry, it is incredibly difficult to achieve. I believe it is impossible to go into such a deep meditation by missing Bodhicitta. First you will become a Buddha, and then, if you wish, you can leave the world by stopping your breathing. If the question is out of curiosity, then yes, it is possible. Buddhist monks often practice leaving the world through immersion in deep meditation, stopping breathing and preserving the body for posterity. Funny guys.
It is impossible to die holding your breath - the instinct of self-preservation will prevent it. But if you can somehow magically remain calm during meditation, shutting your mouth and nose, you will lose consciousness, as a result of which breathing will be restored, because this is a reflex that does not require conscious control.