I did something similar during a course on presentation skills, but on the subject of autism (and did not say I had it, but they guessed). We were allowed to pick any topic we desired. I received positive feedback for addressing a complex subject and conveying information the others had never been exposed to. The tutor specialised in teaching communication skills, so this information was particularly useful for her.
At a later occasion during the same course, I suffered shutdown and lost speech during another presentation I gave. The class, having heard my previous talk, were very understanding when providing their feedback as a result.
I was involved in Dept 56 Collector's Village Miniature House Club. I was kinda cohearsed into doing a how-to demonstration. Well, after the demonstration and the applause. I came out to the group about my Socail Anxiety. I got another round of applause for the extra information. After the coming out, I just wanted to vomit and wish I hadn't shared that information.
Although, a few people came up to me and said they also had Anxieties of their own and were glad I shared this information.
So I'm sure, if you look at your situation, you just may help someone know, their not alone.
I think if you admitted you had social anxiety, people would see this as very real and you aren't going through the emotions. This isn't in a ****ing textbook - it is real and it is affecting your life. People will be able to see this on you and they will probably be able to relate to you in some way.
I opened up to a bunch of classmates once about atheism in a public speaking course despite 95% of the class being Christian. I didn't say people shouldn't have the right to believe what they want to believe; I just wanted to make a statement about what it is as opposed to ignorance society has about the subject.
After I gave the presentation the next day, an older woman in the class the next day told me privately she was really impressed with my bravery. I was shocked and I really appreciated her support and sympathy. The rest of the class (despite being very religious) didn't say a word to me about it. I feared discrimination in a very discriminative world (referring to religion - please lets not start a debate about this - its just how i feel), yet people still treated me like a person and I wasn't rejected.
I hope this motivates you. I also think if you don't give this presentation you might regret it. If you feel it would be too much to admit something so private like SA to a group of people, then I wouldn't suggest doing it. It's up to you.