diff --git a/src/models/event.ts b/src/models/event.ts
index 72c6212db9a..d32f9d7b074 100644
--- a/src/models/event.ts
+++ b/src/models/event.ts
@@ -1339,7 +1339,7 @@ export class MatrixEvent extends TypedEventEmitter<MatrixEventEmittedEvents, Mat
             this.emit(MatrixEventEvent.LocalEventIdReplaced, this);
         }
 
-        this.localTimestamp = Date.now() - this.getAge()!;
+        this.localTimestamp = Date.now() - (this.getAge() ?? 0);
     }
 
     /**