My advice—smile. Make that speech all about the positive—how much fun you have, how much good work you do, how much the kids benefit from your good work. Avoid pitching your big fundraiser and avoid focusing on all the help you need. Both of those things go way better when you start with the fun and helpful stuff.
My second piece of advice is that there's no law that your president has to give that speech. Do you have a volunteer or leader who is a natural in that setting? Use her instead. Your group is always best served putting the right people in the right roles. Just as you don't have a treasurer who can't add, don't have a shy, nervous speaker give your welcome speech.
For more helpful tips, check out our brand-new Quick Tips video on giving a great open house speech.
Good luck!