I think it all comes down to your confidence level. The university I study at had a PWS as the ex-head of its debating society. The person has "overcome" his stutter in the sense that he is confident enough to speak in public because he doesn't "think about the consequences". Though I didn't get to interact with him much, the conversation we had (since I'm a PWS as well) was about how he kind of forced him into controlling his speech behaviour. I'm not sure how though, but I'm glad it worked for him. I think you could definitely try. If you're adamant about it and stay committed, I believe you will find your way through it. I personally believe that debating should be more about the content you deliver than how you deliver it (though a lot of people would beg to differ), so I think you can put more emphasis upon your content and if you're a valuable addition to your team in the sense that your arguments are solid, you'd probably face more acceptance which would give you a push. I hope you have a good experience in debating. All the best!