I would suggest you to make a new scene. Save the pose you did for her, make a new scene, load V4, the sheet and put your slider to the frame 20. Now put her in pose and go to the cloth room. :)

 

When you want to delete frames, click on the key from your animation slider

You got this pop up.

La vie est éternelle. L'amour est immortel.

“Dwell on the beauty of life. Watch the stars, and see yourself running with them.”
― Marcus Aurelius,