diff --git a/internal/session/lifecycle/lifecycle.go b/internal/session/lifecycle/lifecycle.go
index b291fee..c04473d 100644
--- a/internal/session/lifecycle/lifecycle.go
+++ b/internal/session/lifecycle/lifecycle.go
@@ -181,5 +181,7 @@ func isClosedError(err error) bool {
 }
 
 func (l *lifecycle) StartedAt() time.Time {
+	l.mu.Lock()
+	defer l.mu.Unlock()
 	return l.startedAt
 }