Winnie's skeptical. Should she believe the Tucks or not? They certainly believe it, and the narrator seems to side with them. Remember, we learned at the beginning that the Tucks "had all looked exactly the same for eighty-seven years" (2.21).
By telling Winnie their secret history, the Tucks reveal things about themselves, too. Jesse is excited and carefree; he's swept up with the magic of living forever. Miles is more steadfast, concerned about the downside.
Mae says that the most important thing is that nobody else finds out. They need to go speak with Tuck.
Winnie agrees to go with them. (After all, she still thinks Jesse is super cute, so why not tag along?) All four characters make their way back to the Tucks' house, but they're not alone. (Dun dun dun) The guy in the yellow suit has caught up with the Tucks and Winnie. And it turns out he was eavesdropping on them.