Make peach syrup by heating peach juice with a little sugar in a small saucepan over medium-high heat until thickened. Add more sugar, to taste, if desired. Remove from heat and let cool to room temperature.
Place 2 to 3 scoops sorbet in a parfait glass. Drizzle peach syrup over sorbet and place wafer cookies around scoops. Garnish with fresh mint.