Vintage acid wash Steffano knee length skirt

This is from my moms closet. Too small for me- 13 inch waist (I need another inch or so) falls 19.5 inches from waist, has 4inch slit in back. Front pockets. Belt loops. No back pockets. I love this skirt and I wish it fit. Says it is a size ten- I think it's a modern 3 or 5- or size 4 in H&M/ Zara terms.