it depends how many coils per inch you have, or how tightly coiled your hair is. my aunt has waist length natural an when completly natural its still past bra strap length. i have a cousin with waist length natural, an when completly natural her hair shrinks all the up to a couple inches past shoulder. so it really depends on your individual coils.
i think for most 4a ppl, the shrinkage would be somewhere past shoulder lenght.