Please don’t put yourself down in front of an audience.
I don’t think self-deprecation helps anyone. I think it damages a speaker’s credibility and their apparent value. It literally deprecates by conveying self-disapproval. I’ve seen several speakers say “I’m not good at public speaking”* and then do a pretty good job.
I think self-deprecation can become a habit (particularly among us Brits) that we feel will somehow endear us to our audience. Most of the time I see it being used, however, it backfires and I feel that the speaker doesn’t believe in or trust themselves. Consequently, I don’t either.
On the other hand, pointing out your error or weakness with a smile on your face, embracing it and moving on as if it doesn’t really matter (and it probably doesn’t) strengthens your credibility and value by showing us that you DO trust yourself.
Much better.
*They may believe this completely and are therefore being genuine, which is a question of self-awareness, but I still think it’s dangerous to diminish oneself in this way.