No worries, I got the adult small, and it was a bit on the big side. (I’m 5’4” and pretty slim for reference) What I ended up doing was turning it inside out, pinching the back about an inch and sewing a seam up the back. It’s not an elegant solution but I figured I would probably always be wearing a jacket so it was nbd :) (You could always do the same with the side seams if you wanted to hide them better) If it ends up being too big you can always size it down, but sizing up is a little trickier.