I'm glad it went well for you and no teacher should reduce your grade because of this. As for what drink, it's really up to you. the reason I said don't drink coffee because it accelerates your heart beat and that may cause you to stutter more (at least from my personal experience), I don't consume energy drinks and really can't say anything about them, but my advice is to "experiment" with them beforehand and see how better or worse they make you feel about stuttering . For me I like drinking tea or water before having a presentation.