What excuse does Jesse give Winnie so she will not drink the water in tuck everlasting?

In "Tuck Everlasting," Jesse Tuck tells Winnie that the water from the spring is special and should only be drunk when she is ready to live forever. He emphasizes that the decision to drink the water is significant and irreversible, implying that it would change her life permanently. Jesse's approach is meant to make Winnie think carefully about the implications of immortality before making a choice.