You can't live like this. You can't thrive with such a fearful mindset. Aren't you just over it by now? We're the same age, and I've done my share of presentations and I've fought against this mindset so much. It's not the end of the world if you stutter; even if you don't stutter it could still be a bad presentation. Hell, I'm be open to the idea of advertising your stutter before the presentation. If life is just a series of challenges to avoid stuttering you're setting yourself up for constant failure. And for the rest of the world, fluency isn't "winning."