How long will it take you to do this introduction? A minute or two, or not even that?
If you've been asked to do this, do it if you can. It'll all be over and done with in an instant and you'll be glad you did it. I would.
If they'll let you have notes with you that you'd be able to prepare beforehand, so much the better.
On Sunday I spoke to about 120 people, giving a testimony on my life before, during and after becoming a Christian. It was funny, because I'd tried to script and remember what I was going to say as much as possible. My minister, who was interviewing me, told me to just make my speech from the heart and not to rely on notes. At least the notes helped me remember what I wanted to say.
Meanwhile, the speaking wasn't difficult for me and it went down really, really well.
I have also read the Bible in church once or twice, again not difficult.