The formal telling of the story of Passover is framed as a discussion with lots of questions and answers.  The tradition that the youngest person asks the questions reflect the centrality of involving everyone in the seder. The rabbis who created the set format for the seder gave us the Four Questions to help break the ice in case no one had their own questions.  Asking questions is a core tradition in Jewish life. If everyone at the seder is around the same age, perhaps the person with the least seder experience can ask them - or everyone can sing them all together.

haggadah Section: -- Four Questions
Source: Jewish Boston