How about a nice "old" song?

Introduce it by saying that in honor of the occasion you've got a special song, just in her honor.

(To the tune of "Silver threads among the gold".)

Supposing her name is Helen, it would go:

Helen, you are growing oh-old
Rocks don't get as old as you.
You're not quite as old as God is
But you're older than primordial stew.

Yes, my Helen, you will bee-ee-ee
Older than the rocks and trees.
Yes, my Helen, you will bee-ee
Older than the rocks and trees!"

I've used it a number of times over the years, and it's always been well received.

Dave Oesterreich