Just reading this gave me huge anxiety. I know that it's probably unpopular opinion and might be seen as running away from problems but you can turn it down. I wouldn't call this cowardice because well, we're disabled so things like that are HUGE stress for us. Honestly situations like that are traumatic to me, it would worsen my self esteem if I did bad during the presentation. All I wanna say is that you don't need to feel bad if you'd like to cancel it. Stay strong buddy <3