At 100, there may be a lot of grandchildren to remember. Asking who everyone is once again feels completely fair, especially when the whole family has arrived to celebrate.
This is a fun birthday meme for a grandparent with a big, growing family. The grandchildren will understand the question, and everyone can share a laugh without taking it too seriously.
Names may slip the mind, but the love behind a family celebration is easy to remember. At 100, being surrounded by generations of family is something worth enjoying.