Who is younger Laura in Little House on the Prairie season 8?

There isn't a character named "Laura" in Little House on the Prairie season 8. You're likely thinking of Melissa Gilbert, who played Laura Ingalls Wilder in the series.

However, Melissa Gilbert was NOT in season 8 of Little House on the Prairie. The series ended with season 9, and Melissa Gilbert played Laura throughout the entire run of the show.

Perhaps you're thinking of a different character or season? Let me know if you have more details!