Blaino, You should start out with your shoulders low. You also should not think "squeezing my shoulder blades".
You SHOULD think about a rotation of your string shoulder and elbow AROUND your spine -- more or less horizontally. Keeping your bow shoulder and shoulder blade down and back will give you room in your back to pull the string shoulder blade towards your spine.
It sounds as though your are on the right track, it's just that the old advice about squeezing your shoulder blades together is WRONG! All you get with that advice is a colossal wreck of shoulder blades and muscles at your spine -- there's no room for movement.
Have you tried a form master? If not -- DO SO.