SK Hat shopwomens

I have a small head - 21 in & have hard time finding hats that aren't too big & slide down or aren't snug enough.. Is this adjustable or run small

why can't i return this way to big hat? i thought amazon had a 30 day return policy?

Does this come down low on the back of your neck to cover a hairless neckline?

Is this free-return? some reviewers say it is not, but amazon says it's free-return.